SetParent messes with scale and position

Since a few days ago, an object that I instantiate and then call SetParent on suddenly increases it's scale and changes position to 1.75 on it's own. This is weird on it's own, but the stranger thing is that I'm working in a team which uses version control, and this is only happening to me. For everyone else in the team, when they run the same scene the scale stays at 1 as expected, which is also how it worked for me up until a few days ago.

The only substantial change that happened around that time is that I upgraded my account to Unity Plus.

Does anyone know what causes this and how I can solve it? I've tried to use SetParent with worldPositionStays set to false, which seems to fix the scaling, but the position stays wrong.