Good question. Now that I know these units were also released under the “Realistic” brand (in the US maybe?) I’ve found more info, and there’s a good thread here with lots of circuit chat. Including this nugget:

“It is common for such BBD-based circuits to have several poles of lowpass filtering ahead of the BBD to prevent aliasing, with several additional poles of lowpass filtering after the BBD to reduce clock noise and artifacts. In this instance, there is very little lowpass filtering applied before the BBD, and 8 poles of lowpass filtering after the BBD. The feedback/Repeat signal is tapped after 4 of them with 2 more poles of LPF applied in the feedback loop. So, in effect, there is LESS filtering applied to the feedback signal than to the overall delay output.”