Timeout with larger pdfs e.g. 10 pages

[RoFrie]

Running paperless 1.4.1 on Ubuntu 20.10
Consumer dir is mounted via NFS, so I use polling instead of inotify.

The scanner writes durectly to the cinsumption directory.
But if a pdf is larger e.g. 10 pages I get the follwing error:
Timeout while waiting on file /..../....pdf to remain unmodified.

I Think there just needs to be some time to wait before a new pdf is polled and consumed.
Is this the right approach? Or what shoud I do else?

Thx
Rolf