Flow_offloading=1 is broken on latest snapshot (4.19 issue)

Nope, that would've been communicated at the various bug reports.
If you have Archer C7 v2, you can use my build from here: https://github.com/MOZGIII/archer-c7-v2-builds/tree/manual-4.19-2019-08-08-1
See instructions here: https://github.com/MOZGIII/archer-c7-v2-builds/blob/master/README.md