The log file says firefox was updated from 68.0.2+build1-0ubuntu0.18.04.1 to 69.0+build2-0ubuntu0.18.04.1 on the 5th of September, then from 69.0+build2-0ubuntu0.18.04.1 to 69.0.1+build1-0ubuntu0.18.04.1 on the 26th of September. Can you confirm that the latter is the update that broke things for you?
The log file says firefox was updated from 68.0.2+ build1- 0ubuntu0. 18.04.1 to 69.0+build2- 0ubuntu0. 18.04.1 on the 5th of September, then from 69.0+build2- 0ubuntu0. 18.04.1 to 69.0.1+ build1- 0ubuntu0. 18.04.1 on the 26th of September. Can you confirm that the latter is the update that broke things for you?