Hi DannVDB,
This does line up with a Microsoft-documented printer issue from February/March 2025: USB-connected dual-mode printers that support both USB Print and IPP over USB could suddenly output random text and unusual characters, sometimes starting with POST /ipp/print HTTP/1.1. Microsoft says that issue was addressed in KB5053657, and it was documented in earlier February/March updates as well. https://support.microsoft.com/en-us/topic/march-11-2025-kb5053602-os-builds-22621-5039-and-22631-5039-19284fef-ba57-440b-a027-2d5eeecb73fa
The PCL XL errors point to a second, very common layer of trouble: driver or PDL mismatch. HP’s guidance for PCL XL problems is typically to reinstall the printer/driver, update firmware, or switch to a different driver family when possible. Microsoft also notes that outdated or incompatible drivers can cause print issues and recommends updating or reinstalling the driver, then restarting the Print Spooler if needed.
The most useful next checks are: confirm whether the affected devices are USB dual-mode / IPP-over-USB printers, compare the exact Windows KBs installed on good vs bad clients, and test with a vendor-specific driver instead of the generic Windows path. If the issue is only happening on one printer family, that strongly suggests a driver/firmware interaction rather than a broad Windows regression.