TYPO3 Core

Yes, this is currently not supported in the implementation, so it's not a bug but a missing feature. t3://record scheme only supports records and not really URIs. So it can only deal with 'identifier' and 'uid'.

The general idea here is to NOT use the RecordLinkHandler for things like that. You should create your own LinkHandler implementation for this, and then support the parameters you need, see https://docs.typo3.org/m/typo3/reference-coreapi/main/en-us/ApiOverview/LinkHandling/Linkhandler/CustomLinkHandlers.html

Conceptually it does not really make sense to weaken this implementation. We might want to think about preventing to show "Additional link parameters" for a RecordLinkHandler - that would however prevent people from creating custom linkhandler implementations where the field may not be available if people extend from the RecordLinkHandler "abstract" then...