As you observed @the_rock some things involving vpnd did change in R81.10. The vpnd process is very old and has a long list of responsibilities that were stuffed into it over the years which started to cause stability problems.
In R81.10 two responsibilities of vpnd were split off into two new daemons: iked and cccd. The former daemon handles IKE negotiations and the latter daemon cccd seems to be related to endpoint compliance. @GrassF it is possible that the vpn shell command you are trying to run has not been updated to reflect this change thus the timeouts, disabling the new iked process with vpn iked disable might fix your timeout issue but I'd advise against trying that, as it is not documented and may cause an outage. Please post the output of these two commands:
vpn iked status
vpn cccd status
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