Has anyone had trouble with speed on their tt

The experience you describe goes beyond simple speed stability issues since most turntables of repute are within reasonable limits.

Your controller switching speeds on a whim is a reliability issue and there have been quite a few cases discussed here and on other forums?
One possibility I would consider carefully is static discharge during handling and operation of the controller. If you have a power block with an external earth binding post nearby, it might be helpful to briefly "ground" yourself as a precaution against damage each time you operate the turntable?
If your supply is already damaged I'd be inclined to get it checked by the manufacturer. No point in suffering any longer! :(
Hope this situation improves.

As moonglum says, static buildup can be an issue. I never had stabilty problems, but the controller on my TW Accustic Raven one, suddenly switched to about 300 RPM, luckily, not with a stylus on the record, or that would have been toast. It was indeed due to static build up and the unit was replced, free of charge, with no quibbles, even though it was 3 years old, now that is service. I don't think spending money on kit prevents maintenance issues, perhaps it should, it improves quality and hopefully, after sales service.

One other thing to try, I found using a good, after market power cord, a lessloss, made a big difference to sound quality, which rather suprised me. I thought if one bit of kit would be immune to a better power cord, it would be turntable controller, not so.

Syntax is right.

Yes from a new $17,000.00 table purchase back in 2008, after complaints a new motor controller was sent to me which the manufactured called , an upgraded motor controller.
Just a poorly designed controller in the first place and the new one wasn't much better.
My ears were telling me there still were problems with this table however mentioning this on the happy owners group I hurt sensitive egos and was called names, really the joke is on them.