Initially this unit would not ignite reliably and eventually developed known issue of igniting front left burner instead of oven so I replaced DSI module with updated newer version.

Worked well for a month and now won't stay lit. Removed lower covers to expose lower burner and both it and broiler burner exhibit same problem: call for heat, ignition occurs almost immediately but igniter continues to fire and flame extinguished about 4 seconds later.

Seems unlikely to be burner/igniter since both main and broiler have same issue, although the broiler is little used and may have had this issue for longer than I realize.

What would be next steps for diagnosing the problem?