IR missiles not locking the sun

[K-dot-B]

None of the available IR missiles give a tone when pointed at the sun. In the attached track I used R-3S missiles, but this can be reproduced whit all of them.

There are old threads from around 2016 saying the missiles on the MiG can't lock the sun, but I distinctly remember getting a tone from the sun about a year ago, so the feature had been implemented at some point.

mig21_sun_no_tone.trk