portamento script export prob

[amp]

so i've programmed portamento's on each instrument within my solo string quintet ( 2vns, 1va, 2vc). All sound great, switch on and off accordingly within cubase.
I export to wav file and find that for 6 bars out 70 or so, on one cello only, there is no portamento?
any ideas why?

[reddiesel41264]

Try realtime export and see if this fixes the problem

[amp]

realtime export certainly does work, thank you but there are noises in the export. These don't seem to be consistent tho, as I exported once and got noises (clicks and pops) and the next time none?

has anyone else experienced this?