NO MIDI at open session


for few months now i have a bug each time i open nuendo (7.1.20 64x NEK / W10x64 / i72600k 3.4Gz / 16ram)
no midi is going in nuendo. i remeber having this for years and the only thing i had to do was to turn off on Midi Thru / or press play… then midi would be received.
but now nothing works. I see some MIDI in on my RME fireface 802 card so all is good there.
the only thing i have to do is to quit nuendo and reload…

anyone have this ?