exception – Magento2: issue with elasticsearch7

After upgrade magento to 2.4 and enable elasticsearch7 every few hours I get the error below and all products in the category disappear.
I have to run the reindex manual, and then everything is fine. Unfortunately, after a few hours, the same problem again.

frontend:

2020-12-30 13:19:59) main.CRITICAL: {"error":{"root_cause":({"type":"query_shard_exception","reason":"No mapping found for (position_category_22) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}),"type":"search_phase_execution_exception","reason":"all shards failed","phase":"query","grouped":true,"failed_shards":({"shard":0,"index":"magento2_product_6_v128","node":"zYNianIkRhOFPo8ETFIcTQ","reason":{"type":"query_shard_exception","reason":"No mapping found for (position_category_22) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}})},"status":400} {"exception":"(object) (Elasticsearch\Common\Exceptions\BadRequest400Exception(code: 400): {"error":{"root_cause":({"type":"query_shard_exception","reason":"No mapping found for (position_category_22) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}),"type":"search_phase_execution_exception","reason":"all shards failed","phase":"query","grouped":true,"failed_shards":({"shard":0,"index":"magento2_product_6_v128","node":"zYNianIkRhOFPo8ETFIcTQ","reason":{"type":"query_shard_exception","reason":"No mapping found for (position_category_22) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}})},"status":400} at /home/user/domains/domain.pl/public_html/vendor/elasticsearch/elasticsearch/src/Elasticsearch/Connections/Connection.php:632)"} ()
(2020-12-30 13:20:05) main.CRITICAL: {"error":{"root_cause":({"type":"query_shard_exception","reason":"No mapping found for (position_category_18) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}),"type":"search_phase_execution_exception","reason":"all shards failed","phase":"query","grouped":true,"failed_shards":({"shard":0,"index":"magento2_product_6_v128","node":"zYNianIkRhOFPo8ETFIcTQ","reason":{"type":"query_shard_exception","reason":"No mapping found for (position_category_18) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}})},"status":400} {"exception":"(object) (Elasticsearch\Common\Exceptions\BadRequest400Exception(code: 400): {"error":{"root_cause":({"type":"query_shard_exception","reason":"No mapping found for (position_category_18) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}),"type":"search_phase_execution_exception","reason":"all shards failed","phase":"query","grouped":true,"failed_shards":({"shard":0,"index":"magento2_product_6_v128","node":"zYNianIkRhOFPo8ETFIcTQ","reason":{"type":"query_shard_exception","reason":"No mapping found for (position_category_18) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}})},"status":400} at /home/user/domains/domain.pl/public_html/vendor/elasticsearch/elasticsearch/src/Elasticsearch/Connections/Connection.php:632)"} ()

backlog:

2020-12-30 13:19:59) main.CRITICAL: {"error":{"root_cause":({"type":"query_shard_exception","reason":"No mapping found for (position_category_22) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}),"type":"search_phase_execution_exception","reason":"all shards failed","phase":"query","grouped":true,"failed_shards":({"shard":0,"index":"magento2_product_6_v128","node":"zYNianIkRhOFPo8ETFIcTQ","reason":{"type":"query_shard_exception","reason":"No mapping found for (position_category_22) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}})},"status":400} {"exception":"(object) (Elasticsearch\Common\Exceptions\BadRequest400Exception(code: 400): {"error":{"root_cause":({"type":"query_shard_exception","reason":"No mapping found for (position_category_22) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}),"type":"search_phase_execution_exception","reason":"all shards failed","phase":"query","grouped":true,"failed_shards":({"shard":0,"index":"magento2_product_6_v128","node":"zYNianIkRhOFPo8ETFIcTQ","reason":{"type":"query_shard_exception","reason":"No mapping found for (position_category_22) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}})},"status":400} at /home/user/domains/domain.pl/public_html/vendor/elasticsearch/elasticsearch/src/Elasticsearch/Connections/Connection.php:632)"} ()
(2020-12-30 13:20:05) main.CRITICAL: {"error":{"root_cause":({"type":"query_shard_exception","reason":"No mapping found for (position_category_18) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}),"type":"search_phase_execution_exception","reason":"all shards failed","phase":"query","grouped":true,"failed_shards":({"shard":0,"index":"magento2_product_6_v128","node":"zYNianIkRhOFPo8ETFIcTQ","reason":{"type":"query_shard_exception","reason":"No mapping found for (position_category_18) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}})},"status":400} {"exception":"(object) (Elasticsearch\Common\Exceptions\BadRequest400Exception(code: 400): {"error":{"root_cause":({"type":"query_shard_exception","reason":"No mapping found for (position_category_18) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}),"type":"search_phase_execution_exception","reason":"all shards failed","phase":"query","grouped":true,"failed_shards":({"shard":0,"index":"magento2_product_6_v128","node":"zYNianIkRhOFPo8ETFIcTQ","reason":{"type":"query_shard_exception","reason":"No mapping found for (position_category_18) in order to sort on","index_uuid":"gGtbpx6JSEODjM5Jx_EvuA","index":"magento2_product_6_v128"}})},"status":400} at /home/user/domains/domain.pl/public_html/vendor/elasticsearch/elasticsearch/src/Elasticsearch/Connections/Connection.php:632)"} ()