The TLS key schedule looks like this:
QUIC effectively exports the various traffic secrets, so I had assumed that its use of the different base label in
HKDF-Expand-Label() would be limited to those uses that were after that export. I forgot key update when writing this up, but that was fixed in #1899.
However, in looking at what people implemented, it appears that the base label they use was used for the entirety of the TLS key schedule.