This happens both in brewt and nessa template sets (not sure about wap). Just after sending mail, each link on the interface gets that additional t=<%t%> in the url. Once clicked the subsequent navigation after that does not have that extra t=<%t%>.
say in nessa just after sending mail the links have
...;t=nessa;t=nessa;....
similarly in brewt
...;t=brewt;brewt;...
This is oserved only after just sending a mail. Though this does not give any navigation error but it needs attention as it seems to be there right from 2.1.0 (the version of my live install). Also what needs to be corrected in templates may please be posted.
Also many places both t=<%template%> and t=<%t%> is found. Why have two tags for the same thing?
Thnx
Anup