Something weird happens in Reaper 5.24 when you switch views in Modular V2. It resizes the Reaper window (even if maximized), then it doesn't resize the plugin window again when you change views again. I'm not sure if this happened in previous versions.
I see weird things when increase/decrease size via +- button inside ModularV. But I don`t use this button, only key/seq/osc sections shortcuts. They works ok for me.
I've noticed this as well, and it's been happening for at least a few versions. I've only been using the Arturia V collection for about 10-11 months now, and the Modular V2 has been doing the window resize thing for at least that long.