There is currently a bug when you use the keyboard to apply a transformation to a part/group.

The correct procedure is as following:

• Press the key "R" for rotation or "T" for translation.
• Press the key "X", "Y", or "Z" key to select the transformation axis.
• Enter the transformation value - you can use the minus key "-" to toggle between negative and positive values ("BAK" key to initialise the value).
• Press "ENTER" to validate

Press the "ESC" key anytime to cancel the transformation.

The bug occurs if you don't press the "ENTER" key to validate and use the mouse to perform other actions. The part/group is not synchronised anymore and can end up in random position.

[update] I tried to replicate this bug, but didn't manage to... I might have changed something in the code recently that fixes it. I'll keep an eye on it anyway.