Gearing differences

Can someone explain why on some rides going up hills it’s a grind. I’m in my granny gear pounding away like I would be in real life. Very realistic and I love it. Then like today same hills no grind I’m spinning in the big gear doing 95 rpm up the hill. What and or who makes this change? It’s really irritating and I’d like it to stop.

Did you change the trainer difficulty in your settings?

Depends on the gradient of the hill, you may find a 4% grade easier than a 10%.

Sounds like your trainer failed to adjust to the correct resistance. I’ve had this happen once and I was essentially riding on a flat course even when up hills.