Package being published as stable version instead of prerelease

I keep running into a bug where one of my packages gets published as a stable version, instead of the intended prerelease version. I wasn't able to reduce the problem entirely yet, but due to limited bandwidth I figured I would at least log what I have thus far.

Given two change files that both want to bump a prerelease version:

1. https://github.com/microsoft/graphitation/blob/17694def96c9bfc43b4a39c57ac30a5d0a510edd/change/%40graphitation-apollo-react-relay-duct-tape-8977b470-e2cd-4530-b056-a4d1c7b8f3c4.json
2. https://github.com/microsoft/graphitation/blob/17694def96c9bfc43b4a39c57ac30a5d0a510edd/change/relay-compiler-language-graphitation-d4a68aba-a191-43fa-961f-b1cd49a07927.json

…where 1 has a dependency on 2, this line ends up using the dependentChangeType of the change file (which is patch rather than prerelease) and then uses that instead of the original prerelease change type of 1.

One thing that's unclear to me Is wether dependentChangeType in the change file(s) is supposed to be patch when type is prerelease?

Start in src/bump/updateRelatedChangeType.ts, especially the handling referenced at lines 44 and 75-78, and compare it with the two linked change files. Reproduce the dependency case where both changes request a prerelease, then establish and test the expected handling of dependentChangeType so the published version matches the intended prerelease behavior.