[BUG] MFC-L2710DW duplex printing - all reverse sides are unreadable with artefacts

[disk0x]

Describe the bug The printer MFC-L2710DW is connected to this Linux machine over IPP. Single-side printing works as expected, but when asked to print duplex, all reverse pages are unreadable with artefacts that look like barcodes. This occurs with any type of document (e.g. Postscript or JPEG -- although as far as I understand this shouldn't make a difference because the specific printer only supports GDI)

Steps to Reproduce

1. Print a document in duplex mode
2. See reverse side

Current behavior The reverse page consists of barcode-like artefacts

Expected behavior The reverse pages should be printed

Screenshots

Desktop:

• Operating System: Fedora Linux 38 (6.4.15-200.fc38.x86_64)
• brlaser Version:

  Name: printer-driver-brlaser
  Version      : 6.2.6
  Release      : 1.fc38
  Architecture : x86_64

Additional context The printer is connected wirelessly over IPP

EDIT: When brlaser is removed and the package foomatic-db-ppds is installed, the duplex functionality works as expected, which further narrows down the scope of the issue.

[tssmits]

Similar behaviour for the HL-L2310D.

Single-sided: OK Duplex long edge: Same artifacts as this issue Duplex short edge: OK

[j000]

And the same behaviour on DCP-L2512D on Gentoo (even Brother calls this "DCP-L2510D series" under Windows). Single-sided: OK Duplex long edge: Same artifacts as this issue Duplex short edge: OK - but it's actually printed as duplex long edge.

So I patched source to never send \033&l1S, only \033&l2S, and rebuilt. I never used brlaser before, so I have no idea if it's some updated library/cups causing this.