Fitness Tracker Indoor Cycling Calories Off

I have been using my watch to track my calories for indoor cycling for almost six months now. I have built up to 50-54 minutes. I typically get 220-240 active calories for each 50-54 minutes on the bike. The past two/three weeks, although I am doing the same time, my heart rate is around the same, my weight, height, etc., has remained the same, it has started showing 120-135 active calories instead of the typical 220-240. Some of my previous sessions that were shorter and my heart rate considerably lower showed more calories burned than what I am getting now.

• I checked my health stats. They are the same, and they are as they should be.
• I restarted my watch and my phone.
• I did go to privacy -> reset calibration data.
• I followed that with another restart of my watch and phone.

Is it an issue with the fitness tracker when using indoor cycling? I did notice another post complaining of the same issue. I didn't look beyond that particular discussion, but I will continue to search.

In the meantime, do you have any suggestions as to why this is happening? Do you have any suggestions, other than those I have tried, as a way to fix the issue?

I wanted to add, I matched it against the calorie tracker on my bike as well as a nutrition tracker I use. It is off by at least 140 calories.

Thank you,

Kelly