T RO9, Calbe/adox apho9,Etc does not do as well as the rodinal/ro9one shot/adonal we love today, It tends to crystalize badly and when I used it, and I did like the results, I would buy a litre bottle, the only size available at the time, but over two bottles I dumped around a third of the litre as it lost potency and was more crystal than liqued, so I went back to first of all Rodina, then RO9 one shot from Maco/Rollei, and never had a problem with it,I see lately that Adox are now selling the APH09 in 500 ml containers, amd the other ro9, which is the Foma, and is the same older formula as the APH09, is sold in 250ml containers, so if the OP was using the original RO9/apho9 type then it is possible to have a failure,
Richard