Sliding window panels aren't showing

[vanderloo5]

I've never had this problem before but now all of the sudden I'm having it in multiple projects.
Some sliding windows I insert show the window panels and others don't. Sometimes I insert the same exact window twice, 4 feet apart, and 1 will show the panels and the other won't. It usually happens when I'm using plan regions but not always.
I've changed the view range to multiple ht's and nothing makes the panels show. These are out of the box revit windows. Seems like a bug to me.
Anyone know a fix?
Thanks

[PijPiwo]

Even though it’s a OOTB family, could you upload it anyway, so we can troubleshoot?

[vanderloo5]

I actually did change this window very slightly. It's the standard OOTB slider with trim, with the trim removed. But this isn't the only window this is happening with.
Try inserting it at 6' 8" header height as a 48"w x 1'h
Thanks

[PijPiwo]

The family is ok and I cannot recreate your issue here, it works fine for me. What exactly do you mean by panels? The entire window doesn’t show or just some of its parts (any screenshots?). The only thing I can think of right now is make your plan region bigger in the front and back of the window. Sometimes when its boundary lines are too close to the window, window doesn’t show.

[vanderloo5]

I guess my solution is to draw an invisible model line down to where the cut line wants to be. Even though the actual window is entirely above that line??