Describe the bug
I recorded an off-cpu profile, opened the flamegraph, filtered in on a thread, switched it to off-cpu, and got this garbled mess.

To Reproduce
Open the attached .perfparser file. In the flamegraph tab, filter in on RHIThread, then switch to off-CPU time.
perf.perfparser.zip
Version Info (please complete the following information):
- Linux Kernel version: 6.16.8
- perf version: 6.16.8
- hotspot version (appimage? selfcompiled?): 1.5.80, from the appimage