That looks pretty normal to me. I do the same thing when I’m doing longer intervals that are outside my comfort zone.
A higher cadence tends to raise my HR and breathing, but reduces the strain on my legs and knees.
You can definitely train yourself to maintain a steady cadence. Practice makes perfect in that regard. And it’s an extra skill when you need it.
Personally, I’d try getting out of those high gears on the trainer. You’d be surprised how much you have to smooth out your pedal stroke when the flywheel isn’t filling in the gaps.