I seem to be experiencing your pain. Last week my bike tripped the FI light and threw error code 26. The longer I rode the lower the RPM was that I needed to maintain to trip the error, this was in 30°C+ temperatures. It started off tripping when I held over 4500 rpm, but by an hour later, 3900 rpm would activate the error.
This morning I rode in and the ambient air temp was 18°, ran 4200 rpm for 10 miles, no issue, 4500 rpm for awhile no issue and the last few miles I held 4800 rpm, never an issue.
Temperature shoudl be back up in a week, we'll see what happens.