Ramp Test - Cadence Crash/Trainer Resistance Spike

So, took a Ramp Test today and my heart and lungs felt amazing. I felt like I had more in me, but in the last 3-5 minutes of the test I just couldn’t get my cadence up above 70-80 RPM. I felt like I was fighting my trainer the entire time, I had the heart and lungs but just couldn’t grind through the insane resistance my Kickr 2018 was putting out.

I had to unclip one foot to adjust a pedal mid test but otherwise totally normal test. I’ve never had cadence be the wall I slammed into before. I’ve always just been gasping for air and had to stop. I’m using power match and did calibrate my power meter before test start.

Is this just a new sort of failure I need to adapt to, or is this a trainer/equipment glitch? I’m fine with my result, I increased by about 13 watts. I just felt like I had more in the tank if I’d been able to spin at my natural cadence (around 90 RPM).

Thanks for your thoughts!