can a sealed cap be written to MTCC/STCC?

[tariqkurd-repo]

CSpecialRW of a sealed capability to an SCR which extends a CSR with any 
non-preserved bits clears the tag on the capability, even if the address 
would not be changed.

For this text - I think this must refer to xTCC which extend xTVEC - because of the MODE field in address[1:0] - bit[1] can never be set. The SAIL calls the standard RISC-V legalize_tvec which checks the MODE field is legal before calling update_cap_with_integer_pc which does the representability check. I don't see any code which clears the tag on sealed writes to xTCC though.

What's the correct answer, and have I understood the spec correctly?
FWIW my vote goes with the SAIL.