P: Undo function fails and applies a preset instead

[FeedbackCommunityMember]

LR4.2 When removing a photo from a collection and then pressing "undo" the photo is not returned to the collection and instead a preset is applied to the next photo.

[EdwardJohnAllen]

(Please see screenshot below)
I had a series of images selected, but wanted to close Lr, so hit File/Exit. the program didn't close but instead I noticed that all the selected images had changed and that a preset of mine (highlighted in the LH column) had been applied to them.

(This has happened before when I have tried to exit the software, but with other listed presets being applied. I am quite sure after having seen this a few times that I am NOT hitting the preset by accident!)

I then tried Ctrl-Z to undo, but nothing happens, so I went to the Edit menu and saw that the undo command (first item on list) read " Analog Efex Pro". This seems very odd, especailly as I do not have Analog Efex Pro installed! I do have Silver Efex Pro but rarely use it.

So firstly I think this is a bug of some sort that requires investigation, but secondly, can anyone PLEASE help me undo the preset applied to 60 images that were all individually and lovingly tweaked for high quality printing, and now all have this same preset applied to them. It will take me ages to try and recreate the looks of each one!!!! (I have gone to the "History" menu for one of them, but don't seem to be able to "undo" from there either)

PLEASE HELP ME RESCUE MY IMAGES!!

thanks in advance