Maybe Fission related. (DOMFissionEnabled=1)

Crash report: https://crash-stats.mozilla.org/report/index/9ff07fd8-edf9-4dd2-bbcf-9f8a90220319

Reason: EXCEPTION_ACCESS_VIOLATION_READ

Top 10 frames of crashing thread:

0 xul.dll mozilla::dom::FetchStreamReader::CloseAndRelease dom/fetch/FetchStreamReader.cpp:184
1 xul.dll mozilla::dom::WeakWorkerRef::Notify dom/workers/WorkerRef.cpp:133
2 xul.dll mozilla::dom::WorkerPrivate::NotifyWorkerRefs dom/workers/WorkerPrivate.cpp:3954
3 xul.dll mozilla::dom::WorkerPrivate::NotifyInternal dom/workers/WorkerPrivate.cpp:4570
4 xul.dll mozilla::dom::WorkerRunnable::Run dom/workers/WorkerRunnable.cpp:377
5 xul.dll mozilla::dom::WorkerPrivate::ProcessAllControlRunnablesLocked dom/workers/WorkerPrivate.cpp:3706
6 xul.dll mozilla::dom::WorkerPrivate::DoRunLoop dom/workers/WorkerPrivate.cpp:3017
7 xul.dll mozilla::dom::workerinternals::`anonymous namespace'::WorkerThreadPrimaryRunnable::Run dom/workers/RuntimeService.cpp:2165
8 xul.dll nsThread::ProcessNextEvent xpcom/threads/nsThread.cpp:1167
9 xul.dll mozilla::ipc::MessagePumpForNonMainThreads::Run ipc/glue/MessagePump.cpp:300

There are 9 crashes (from 7 installations) in nightly 100 starting with buildid 20220319094158. In analyzing the backtrace, the regression may have been introduced by patch [1] to fix bug 1750298.

[1] https://hg.mozilla.org/mozilla-central/rev?node=4ec8f7211b07