Strange behavior when using vi editor mode.
It goes something like this, with "|" being cursor:

%: bindkey -v
%: mv /some/file /some/other/file
commands: <ESC>Bi
%: mv /some/file |/some/other/file

At this point I can type in new stuff just fine, and <BS> up to the point
where I reentered insert mode, but anything earlier than that beeps and
doesn't delete. Stranger still is when I <DEL>

%: mv /some/file /SOME/OTH|er/file

Changes it to caps.

I'm using version 5.0.6 and have reproduced the error on multiple x86_64
machines with default configuration.

Since no one else seems to be reporting this bug and it's so severe I
figure it's likely there's something I just don't get. If that's the case
I'm sorry for all the trouble, but can you let me know what's happening?