This is a known issue and has been reported multiple times to Embarcadero but it hasn't been fixed.
There is no difference between XE4 and XE5 in the mCL source code except for some units so we suspect that the issue is lying in the FireMonkey framework.
Until now, there isn't a solution or workaround for this issue and I suggest to stick with XE4 for mCL if you have that environment installed.