a) The release notes state that "the base VFX64 does not include an FP pack". In fact, NDP387 is in the base system. If you need SSE64 then you have to remove NDP387 first. The documentation does not highlight that the NDP387 recogniser also needs to be manually removed - see my other post.
b) The compilation of FPSSE64S.fth leaves a couple of items on the number stack. These are non-functional problems, but on our build they flag an alert. The problem is a couple of NIP s missing. Line 307 etc. should be ...
c" FP-PACK" find NIP FPsystem SSE64System = and
dup [IF] cr ." SSE64System pack already compiled" [THEN]
c" FP-PACK" find NIP FPsystem 0<> or
[IF] cr ." Remove existing float pack before compiling this one" abort [THEN]