Hello! 
When I place an instance with the angle changed to 90º, 180º or 270º in X = 0 and/or Y = 0 even using grid a strange number appears:
I don’t know if with angle 0 it can be reproduced. I couldn’t here.
Oh, and I changed the setup of grid 32/32, 16/16 and 8/8 but the same problem occurs.
Thanks.
This is scientific notation of numbers, so it’s something like 0.(15 zeros)1776356…
If you replace it with 0, does the 0 stay?
Yes, the 0 stay. I changed it in all my external layouts to prevent something going wrong in the future.
It’s just a way of writing long numbers in small boxes, it shouldn’t cause any issues.
Right, but I think it is necessary to take into account that when positioning these instances with grid activated we expect it to be 0. I did a quick test here and these scientific notation of numbers do not correspond to 0 which can cause problems with events (checking the position, for example). In addition, it generates more work and requires more attention when building the scene in order to avoid having these unwanted numbers (if the developer know about them).
My little test:
Sorry if I wasn’t clear. I meant it’s a proper number and shouldn’t cause any stability issues (bugs, crashes and such).
You’re right, it’s not zero and might cause problems with conditions checking for a specific position value. 
As such, it should be fixed.
