[master branch] Strange problem while fetching symbol from certain module

[Nala Ginrut]

Hi folks!
I'm using master branch(2.1) for a while, since it's faster than
guile-2.0. But I encountered a problem after repo updated.

---------------------------------begin---------------------------------
scheme@(guile-user)> (@ (rnrs) bytevector?)
ERROR: In procedure #<procedure 185b520 ()>:
ERROR: In procedure private-lookup: No variable bound to bytevector? in
module (guile)

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]> ,bt
           0 (#<procedure 185b520 ()>)
---------------------------------end-----------------------------------


Any hint for that?

Thanks!