It happens regardless of model or FrSky or ELRS or whatnot... when I quickly move TLite gimbal left, the value decreases but.. takes over 0.5sec to show -100. It doesnt happen on pitch or yaw.

Well from your description it clearly doesn't sound like it's a model specific related issue.

I assume that you've tried recalibrating the sticks? If not then try doing that first.

If that doesn't work then take a complete backup of the SD Card and then reformat it and load on the vanilla SD Card contents (from HERE) for the version of EdgeTX that it's running which will leave you with the default EdgeTX hardware settings for your transmitter and no models, so you will then need to create a new model from scratch again, or copy the MODELS folder back to the SD Card form the backup you took of it. It might be worth trying to create a brand new model first just to rule out any anomalies with the settings against the original models.

If that still doesn't fix the problem then try re-flashing EdgeTX firmware to your Jumper T-Lite. Don't forget to flash both the main firmware and also the bootloader.