I just debugged into source code and it's definitly a bug caused by the fact that style classes dr-sdt-c-0 (1,2 and so on for each column). If the user tries to adjust the width the first (the one of the first scrollable data table) definition dynamically adjusts but the second always overwrites this.
My guess is that either the column id or the id of the scrollable data table must be inserted in that dynamically generated class definition.
Can this be fixed in 3.2.1?
Maybe I could try to fix this as well and post it somewhere (?) if someone of the RF team could tell me how I can do some string manipulation within the JSPX templates as I need to manipulate the clientId (either replacing ':' by '-' or just doing a substringAfter).