I'm far away from saying that there is no bug in Dekko2, but if finding below is a bug in Dekko2 or a new bug/feature/behavior in the OS is unclear. The high CPU utilization of dekkod is a result of reading from time to time again through one of its database files /home/phablet/.cache/dekko2.dekkoproject/database/qmailstore.db (39 MByte in size) with tons of llseek(2) and read(2) syscalls:
[pid 22511] _llseek(9, 20623360, [20623360], SEEK_SET) = 0
[pid 22511] read(9, "\r\0\0\0\1\1o\0\1o\1\27\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1024) = 1024
[pid 22511] _llseek(9, 20625408, [20625408], SEEK_SET) = 0
[pid 22511] read(9, "\r\0\0\0\1\1v\0\1v\2\214\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1024) = 1024
[pid 22511] _llseek(9, 22777856, [22777856], SEEK_SET) = 0
[pid 22511] read(9, "\r\0\0\0\1\1s\0\1s\2\214\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1024) = 1024
[pid 22511] _llseek(9, 20626432, [20626432], SEEK_SET) = 0
[pid 22511] read(9, ^C"\r\0\0\0\1\1s\0\1s\2\225\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1024) = 1024
...
In it log file it says about this:
[22511] May 13 07:24:41 [Debug] Action completed 96684008800466 result success
[22511] May 13 07:26:39 [Warning] Would not determine server/action completing
[22511] May 13 07:26:39 [Warning] Would not determine server/action completing
[22511] May 13 07:26:40 [Debug] Running action ExportUpdatesRequest 96684008800468
[22511] May 13 07:26:40 [Debug] Running action ExportUpdatesRequest 96684008800469
[22511] May 13 07:26:41 [Warning] Unable to process malformed message removal record for account 4
[22511] May 13 07:26:41 [Warning] Unable to process malformed message removal record for account 4
[22511] May 13 07:26:41 [Warning] Unable to process malformed message removal record for account 4
[22511] May 13 07:26:41 [Warning] Unable to process malformed message removal record for account 4
[22511] May 13 07:26:41 [Warning] Unable to process malformed message removal record for account 4
....
I think it's time to remove the Dekko2 installation completely and start again from scratch. The PITA is that there is no way to keep the configuration, one must configure all by hand from scratch. This is really a bug in Dekko2.