Possibly, but I have upgraded four other Ubuntu machines, and one Windows machine with no problems. Sometimes the WCG Settings get reset randomly I have noticed, and expect that could be it.

If you insist on running a TEST client, set your device profile, custom section to limit the number of tasks to assign on a per-science basis.

To revert to the last stable, 7.14.2, go to https://boinc.berkeley.edu and click the Download BOINC button to get it as appropriate for your operating system.

And still it's a TEST client, nothing set in stone yet.

The scheduler at one time was set to fetch work when a user manually operated the update button... let's not have a connection go to waste even if the buffer is full. If work in automated fashion keeps coming it's likely because the task duration estimation is wrong. Check the DCF which normally should be near 1.000000. Maybe a berserk benchmark is driving that.

Anyway, strange how this rampant work fetching is not a topic on the developer's mailing list v.v. 7.16.3. If it's a concern it should be flagged there.

I would add now that I have three Ubuntu 18.04 machines with BOINC 7.16.3 on WCG, all on the same "location". Two of them exhibit the problem, and just keep downloading until they reach the 10 day limit even though I have the buffer set on one to 0.10 + 0.50 days (the default) and the other one to even less, 0.05 + 0.10 days.

However, the third machine is working properly now, after downloading five days of work (too much). But at least it is not requesting any more. My guess is that something in the PPA version changed, even though they all show 7.16.3. I will uninstall later and try again. Maybe it is fixed. (Or else, maybe WCG is making changes on their end?). Also, there is the possibility of picking up settings from other BOINC projects. They all interact somewhat.