Canon i-Sensys MF750C single page only with duplex ADF

I've been using simple-scan for a bit to can on my MF-752Cdw using the duplex ADF and it's been fine. But I just went to scan and it came back with an error trying to scan.

I noticed there was a f/w update for the printer/scanner so I updated it and now it connects and scans. However it only seems to display a single page from the scan.

The scanner takes all pages and seems to be sending them, but only the first side of the first page is in the output.

This happens with skanlite, skanpage and simple-scan so it seems like it might be an issue with sane.

Output from scanimage -V is:

scanimage (sane-backends) 1.4.0; backend version 1.4.0