Duniter Desktop starts looping for no reason on "The proof-of-work generation was canceled: [object Object]"

Created by: jytou

For the second time in 3 days, my duniter desktop started looping on the following in the logs:

2017-09-10T19:09:25+02:00 - warn: The proof-of-work generation was canceled: [object Object]
2017-09-10T19:09:25+02:00 - trace: PoW loops = 143672
2017-09-10T19:09:25+02:00 - warn: The proof-of-work generation was canceled: [object Object]
2017-09-10T19:09:25+02:00 - trace: PoW loops = 143673
2017-09-10T19:09:25+02:00 - warn: The proof-of-work generation was canceled: [object Object]
2017-09-10T19:09:25+02:00 - trace: PoW loops = 143674
2017-09-10T19:09:25+02:00 - warn: The proof-of-work generation was canceled: [object Object]
2017-09-10T19:09:25+02:00 - trace: PoW loops = 143675

It gets stuck on an old block and doesn't go forward or calculate anything anymore.

When I try to restart it, it gives the following error:

2017-09-10T19:13:14+02:00 - error:  TypeError: Cannot read property 'transactions' of null
    at DuniterBlockchain.<anonymous> (/opt/duniter/app/lib/blockchain/DuniterBlockchain.js:443:36)
    at next (<anonymous>)
    at /opt/duniter/app/lib/blockchain/DuniterBlockchain.js:7:71
    at __awaiter (/opt/duniter/app/lib/blockchain/DuniterBlockchain.js:3:12)
    at DuniterBlockchain.undoDeleteTransactions (/opt/duniter/app/lib/blockchain/DuniterBlockchain.js:442:16)
    at DuniterBlockchain.<anonymous> (/opt/duniter/app/lib/blockchain/DuniterBlockchain.js:406:24)
    at next (<anonymous>)
    at fulfilled (/opt/duniter/app/lib/blockchain/DuniterBlockchain.js:4:58)

And when I restart it again, I get a core dumped. Last time, it did restart correctly and after a sync it was back on track. Not this time. It took 4 restarts until it got back on track and it is now on the latest block.