No really an answer but I need space to share my experience.
I had the same problem with MFC-L2750DW, firmware version 1.1 upgraded before seeing the problem.
I downloaded and installed the scan driver brscan4-0.4.11-1
from Brother
% dpkg -l brscan4
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-==============-============-============-=================================
ii brscan4 0.4.11-1 amd64 Brother Scanner Driver
but this did not help.
Then I found your post and run
% brsaneconfig4 -q
MFC-L2750DW [ 192.168.0.100] Brother_MFC-L2750DW_series
% sudo brsaneconfig4 -a name=MFC-L2750DW ip=192.168.0.100
[sudo] password for :
% brsaneconfig4 -q
* * [ 192.168.0.100] MFC-L2750DW
The output of brsaneconfig4 -q
gained two stars and the feeder began to work normally.
Now I realize that all this is on https://help.brother-usa.com.