Roon Core chokes up since 1.6 (build 390)

Since 1.6 was installed, or possibly a few days later my Roon Core seem to choke up and provide very poor performance when Searching or trying to Share an album.
I mentioned this in the thread about the Search-function as I thought the issue was on the Roon-side.
My Roon Core is hosted most of the time on a QNAP TS-470 Pro with an Intel Core i5 3470T-processor. (16Gb ram and 3*6Tb Wd Red in a RAID5 config. Samsung 128Gb SSD for Roon DB) This is connected to my LAN and WAN via a wireless bridge, which provides excellent stability and good performance.

Problem is, after a reboot of the Core everything is fine. Search is snappy, Sharing does just fine, playing back tracks is immediate. After a couple of days the search speed seems to slow, occasionally. This gradually worsens and a few minutes ago I did the second reboot after 1.6.
Symptoms;
When trying to share an album using Imgur it takes a loooong time for the image to appear (just the animated Roon icon) and then it takes a long time when pressing the Share via Imgur-button again. This often fails and times out.

Search for a new (or existing in local lib) artist takes forever (that’s about 20-30 seconds in an IT professionals world in the year 2019). Repeated search usually goes a lot faster, around 5 sec, but not always.

Right before my reboot of the Core QNAP app I looked at the perf figures for the QNAP and Roon Server was consuming 25% CPU and 3.2Gb RAM… After reboot Roon Server uses somewhere between 1% and 3% while playing back Qobuz.

Any ideas @support ?
@crieke, o you know if the QNAP can give more detailed information about what’s going bad?

Edit:
Added screen shot of performance figures about 30minutes after reboot, while playing back Qobuz: