If users print checks in bulk and finds odd characters like "#ada$!sda@^*!98sa1*())", consider that Adobe prints the check not NetSuite. NetSuite only creates the check in a PDF file and has Adobe open it.
Though this is not a NetSuite issue, as a workaround, in printing checks, wait until the data display in PDF window. When printing, do not close the PDF until the print job is done.
Closing PDF window quickly usually results to odd characters.