qpdfview 100% CPU, loops, no display

Hello,

On and off, I sometimes get the problem I spoke of a long time ago :

https://answers.launchpad.net/qpdfview/+question/678560

As previously said, once the .config/qpdfview directory is removed (renamed), everything gets back to okay.
An strace, when looping/freezing, shows what looks like an active wait on some futexes :

write(5, "\1\0\0\0\0\0\0\0", 8) = 8
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
poll([{fd=3, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=3, revents=POLLOUT}])
writev(3, [{iov_base="&\0\2\0\24\4\0\0", iov_len=8}], 1) = 8
futex(0x7fffb0190be8, FUTEX_WAIT_BITSET_PRIVATE|FUTEX_CLOCK_REALTIME, 0, NULL, FUTEX_BITSET_MATCH_ANY) = -1 EAGAIN (Resource temporarily unavailable)
futex(0x55b8220ae0c8, FUTEX_WAKE_PRIVATE, 1) = 0
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
poll([{fd=5, events=POLLIN}, {fd=14, events=POLLIN}, {fd=19, events=POLLIN}], 3, 0) = 1 ([{fd=5, revents=POLLIN}])
read(5, "$\0\0\0\0\0\0\0", 16) = 8
poll([{fd=3, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=3, revents=POLLOUT}])
writev(3, [{iov_base="+\0\1\0", iov_len=4}], 1) = 4
futex(0x55b8220ae0c8, FUTEX_WAKE_PRIVATE, 1) = 1
futex(0x55b8220ae0c8, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=3, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=3, revents=POLLOUT}])
writev(3, [{iov_base=";\3\5\0\17\0\340\2\0\0\0\0\7\1[\0\264\2\304\3\202\3\n\0\6\0\340\2\17\0\340\2"..., iov_len=76}], 1) = 76
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
poll([{fd=3, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=3, revents=POLLOUT}])
writev(3, [{iov_base="&\0\2\0\24\4\0\0", iov_len=8}], 1) = 8
futex(0x7fffb0190be8, FUTEX_WAIT_BITSET_PRIVATE|FUTEX_CLOCK_REALTIME, 0, NULL, FUTEX_BITSET_MATCH_ANY) = 0
futex(0x55b8220ae0c8, FUTEX_WAKE_PRIVATE, 1) = 0
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
write(5, "\1\0\0\0\0\0\0\0", 8) = 8

(and so on...)

Here are links to the strace data and my (previous) config directory :

https://lufi.ethibox.fr/r/KZTk2PuBnC#N++pHUe4BNsjkhArbRXugW7pQgRZY30wl/eNzIDRzao=
https://lufi.ethibox.fr/r/rnHdh4h20r#NVcCx8IS0awMPnp9q19j1yclaoEWHTAVOHjQDacpltM=

Since this bothers me a lot, I'm ready to help pinpointing this problem (but cannot code, sorry).