Google Drawings text boxes overwrite each other?

When I enter text into a text box in a Google Drawing (either standalone or when created in a Google sheet), every word overtypes the word previous to it. When the drawing is embedded, it looks fine, but in edit mode you get garble like in the attached screenshot. (And because it’s impossible to see what I’m doing, I can’t really fix typos and so on.)

I assume (as always) that this is user error — does anyone know what I did wrong?

FWIW, I’m using Chrome, just the standard install (no beta or bleeding-edge or whatever). I have no extensions that seem relevant (Zotero, LastPass, etc.).

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