Solved

DRS skipped activation one lap

If you had looked carefully at the lap timing chart I have no doubt you would have seen a double yellow flag icon at the same time as DRS was deactivated. This is because a car suffered suspension failure as a result of not being repaired for multiple races.

Also, you will almost certainly find that you are unable to look at detailed lap-by-lap race data because of the DNF.

The Devs are aware of both issues and I believe are looking to introduce a patch when time permits.