[seL4] sel4test:nested timeout fault test flaky?

We run sel4test regularly for a 64-bit raspi target under qemu and occasionally see failures like this:

Starting test 129: TIMEOUTFAULT0003

Running test TIMEOUTFAULT0003 (Nested timeout fault) Error: Check badge(3) == expected_badge(2) failed. at line 9

This is a stock sel4test https://github.com/AmbiML/sparrow-sel4test + dep libs but an older kernel https://github.com/AmbiML/sparrow-kernel.

Anyone know if this is an old (presumably fixed) bug or known issue?

-Sam