The code with a condition `Mod(t, 2 π) == 0`

```
data = Block({d = 0.15, r = 0.3},
Reap(NDSolve({x''(t) + d x'(t) - x(t) + x(t)^3 == r Cos( t),
x(0) == 0, x'(0) == 0,
WhenEvent(Mod(t, 2 π) == 0(*&&t>50*),
Sow({t, x(t), x'(t)}))}, {}, {t, 0, 100},
MaxSteps -> ∞)))
```

It works fine in v11.3, and gives the data as follows

```
{{{}}, {{{6.28319, 0.895631,
0.418075}, {12.5664, -1.21673, -0.312119}, {18.8496, -0.405354,
0.587376}, {25.1327, -0.254392, -0.19556}, {31.4159, -0.40937,
0.151545}, {37.6991, -0.141298, 0.702613}, {43.9823, -1.09087,
1.0678}, {50.2655, -0.921924, -0.607913}, {56.5487, -0.594581,
0.48939}, {62.8319, 1.09998, -0.105309}, {69.115, 1.19792,
0.541834}, {75.3982, -1.09163, -0.417725}, {81.6814, -0.479742,
0.483879}, {87.9646, 0.846189,
0.400168}, {94.2478, -1.28112, -0.186879}}}}
```

However, when the conditions `Mod(t, 2 π) == 0&&t>50`

apply, the data for `t>50`

It is not outdated.

Can anyone explain it? Any suggestions would be greatly appreciated!