Premiere Creates Glitches in Video Footage

Well looky here, another goddamn bug in Premiere.  This time it's adding glitches to video footage that are not just present in the program monitor and exports but become baked into the source clip within Premiere.  This glitch is basically a horizontal band of pixels shifting left or right for one or two frames so the talent momentarily looks like their head was run over by a truck.  The type of effect you normally pay Red Giant for when you actually want to screw up the look of your video for creative purposes.  Of course, we double-checked to make sure it was not in the actual source file by playing the C100 .MTS in VLC - no glitch there.  Yet, there it is in the Source monitor, playing back identically every time as if it WERE baked into the source file.  How 'bout that shit, huh?  Offlining and relinking don't help.  The only fix initially was to re-import the clip and use match frame on the corrupted one to fetch in/out points, then drag into the timeline manually and copy/paste any attributes.  Efficiency?  Who needs that, am I right?  I, for one, love having to recut video clips manually for no other reason than the software is a buggy pile of dung.  This presented on two of our machines but did not present on another.  We discovered that one was running the latest version while the other two were running 12.0.0.  Updating resolved the problem.  Great, right?  But I have to wonder - why did this only emerge after the update was released?  How does a new problem develop in an-already released version just because a new one has been released?  Good God I miss Magix Movie Edit Pro 2004.