Steps to reproduced:

1. Create new project
2. Add reflection probe to scene
3. Notice that its X value of Size is 10 and X value of Probe origin is 0
4. Set Probe origin X value to 10
5. Actual behaviour: Size is increased to 15, new probe origin value is dicreased to 7.5

Expected behaviour: Size is increased to 20, new probe origin value stays set to 10

Note: same thing happens when setting Size value: if origin would exceed bounds of new size, then not only new origin is decreased but Size is also changed.