This has been a problem ever since the first dual-GPU laptops came on the market several years ago.
I'm sure you know this, but many others reading this probably don't: The basic problem is that Photoshop uses the GPU for actual data processing, and the result returned to Photoshop. It's not a one-way flow like it used to be. So Photoshop needs to know which GPU to talk to. The question is whether the laptop manufacturers know this...
You'd think it would be a simple matter to "lock" Photoshop to one GPU and tell it to ignore the other. Since this hasn't happened after all these years - and Adobe cannot possibly be unaware of this - it's apparently not so simple. Maybe the necessary APIs simply don't exist.
New versions tend to introduce new error-checking code, as new GPU-resident functions are added and specifications change in the new version.