Yes, you are running into that limitation, and I told you how to get around it; escape the special characters instead of using them literally.
//tokenize 32 a $chr(124) b $chr(124) | echo -a $1-
Note that this limitation is not unique to mIRC. This is the same issue as in the regular expression syntax. For instance, you cannot have the regular expression matching [] without escaping the [] characters, since they have special meaning in regex syntax. The means for escaping in regex is \[, in mIRC, it's common to use $chr().
