10.4.1 Bug? Playhead jumps when colour correcting

Has anyone else encountered the following?

I click a clip to make a colour correction.
I use the colour boards.
The moment I click a circle to drag it on the colour board, my playhead jumps a few seconds forward in the timeline. Sometimes this means it jumps to an adjacent clip, another shot. Very annoying.
After repositioning the playhead I can drag the circles without the playhead jumping around.

Yes. I've had this same problem consistently! I don't use the color board though. For me it shows up when adding a control point on the Color Curves or Hue/Sat Curves. Sometimes it jumps forward sometimes backward in the timeline. Sometimes it jumps a few seconds, sometimes 20 minutes!
I have discovered that, as soon as it jumps, if I "undo" (Cmd + z), the playhead comes back to my intended frame and I can continue the correction with no further problem. That is, until later when I'm working on another clip. I guess we should report this as a bug. Right?

Filling in a feedback form for Apple as we speak... and it seems I cannot select my MacOS 10.13.4 - the dropdown menu only goes to 10.13.2. Sloppy, Apple, sloppy.

Yes, we've been getting this all the time on 10.4.1 on our 2012 PowerMac, as well as wierd stuff like the playhead suddenly jumping to the very start or end of the timeline. We tend to use the PowerMac system as a 'test bed' for new versions of FCPX / OS before we update our two Retina i-Macs (which do most of our real work). I think we'll hold off updating these for a while longer... We'll send Apple feedback...

1. Yes. It will often jump to the beginning or end. (And I'm on a 1st gen 5K iMac.)
2. It is doing it now no matter what correction tool I'm using. Touching any of the controls in Color Wheels, Hue/Sat, or Curves.

Yes, I've encountered this behaviour while doing colour corrections as well.

Yep. Definitely a bug. I have been using the color wheels and this happen approx. 40% of the time. Very annoying. I've sent feedback to Apple twice on this issue.

Two other things: the wheels (when they don't jump) are an improvement.

Also, the balance color option actually works quite well in most instances. Now, I use it on every shot as a starting point. Often, it's about right 80% of the time or so in find a baseline white balance.

Bad news with 10.4.1: I find it to be super crashy. All the time. I don't lose work, just time. I'm on a fully specced out 2017 iMac 5K with Pegasus Raids for my media.