Thanks for reporting. I have already noticed it, I will check it.

I've got a similar wu stuck at 67% with "time elapsed" proceeding but "time to completion" now blank. I've suspended it for now rather than aborting.
In Windows, I'm sure you can trick such a stuck wu into finishing gracefully by editing the "fraction done" line in the task_state file or progress file if there is one(I've had to do this a few times for stuck T4T WUs), but I'm a linux virgin so wouldn't even know where to look for the equivalent file. I tried to edit the cc_config file to show checkpoints etc. but it said I didn't have permission so even if I find it I might not be allowed to edit.
Hope that points somebody in the right direction.

Update on that WU;
I closed then reopened Boinc Manager to find elapsed time had rewound by about 4 hours but shows time remaining rather than the blank I had previously. Progress bar has also started ticking up so all appears to be well again. We'll see what happens in 2 hours time (past my bedtime so I'll not see 'til morning)

Completed and validated fine. It maybe got stuck at the "No heartbeat message". Took considerably longer than wingman but it was running in a Virtual Box so maybe just the overheads of that. Anyway, all seems well again 8¬)