Even though it was stated that this bug would be fixed by now, and was fixed 2 betas ago, it still hasn't been.
The GUI shrinks itself to -2 no matter what you do once you close the application and re-open it, even though the GUI claims to be at whatever setting I have it on. It fixes if you move the GUI slider off of and back onto whatever option you want it on, but this shouldn't be needed. It makes the inventory way too small unless you remember to correct it every single time.
Please fix this.
As mentioned in your previous report, this issue is being tracked at MCPE-89543. If you have new information to add, leave a comment on MCPE-89543.