DD620 with "odd" statistics

Hi, im new to this forum. We have a DD620 used to receive replication data from 2 different customers, both running local backups to a DD160 using BRMS on a Power7 server. (IBM i) On both the customers local DD box everything looks normal. On the DD620 replication box, one of the customer's statistics looks very odd. When i click the mtree for that customer, and then select 7 or 30 days "written", the red bars that indicate Post-Comp data, are much taller than the blue Pre-Comp bars. Some days i can hardløy see any blue at all. The customer typically backups up between 5 and 600 Gb every day, which gives between 12 and 20 GB Post-Comp data.

On his local DD box all statistics looks normal, with a compfactor of 35-40x. On the DD620 replication box, his compfactor is negative.

The DD620 is running version 5.2.3.1.

It looks like this:

Anyone that can comment on this? A while after installing and setting everything up, we did run a complete server restore at the remote site where the DD620 is situated. We have a seperat Power server there only for DR purposes. We did a boot directly from the DD620 box through direct attach fiber, and we used the BRMS reports to restore the whole server, the application was then tested. That is a few months go.