Problem: Stick input delay (1s) with FRSKY d8r-ii plus SBUS

my camera copter which was running great for two years now has a strange problem all of a sudden: in 1 out of 10 startups, all inputs are delayed for about 1 second (almost crashed it). If the copter is restarted, the problem resists. After 3-4 restarts it does work again…
FC is a Pixhawk 1 original from 3dr.

I did not change any firmware on my taranis or the rx.

Does anybody know about a similar issue?