Cannot compare two JS allocation profiles

I was trying to find out what caused extra JS allocations, by comparing these two profiles: https://share.firefox.dev/3A6kTET and https://share.firefox.dev/3Ywkipy

Comparison URL: https://profiler.firefox.com/compare/calltree/?ctSummary=js-allocations&globalTrackOrder=0w2&implementation=js&profiles[]=https%3A%2F%2Fshare.firefox.dev%2F3A6kTET&profiles[]=https%3A%2F%2Fshare.firefox.dev%2F3Ywkipy&range=m7811&thread=2&timelineType=category&v=10

In the comparison view, the individual threads have a "JavaScript Allocations" entry in the dropdown, but the call tree is empty when that item is checked.
And the diff thread doesn't have a call tree strategy dropdown at all.

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-807)