Glitches/Drop Outs with External FX

hi i got some glitches / Dropouts in the beginning of songs when i render some files in the Audio Montage when i insert a External FX in the inspector to the Clips
i don’t have the problem in Cubase and other DAWs.

i don’t hear it when i play it only after rendering.

is there a workaround ore its a bug ?

thanks