Loads of admin-ajax requests

Hello!
Thank you for the plugin, it was working for us very well for a long time.
Suddenly 2 days ago we noticed that site became very slow (backend as well as frontend). Hosting support pointed out there were a lot of uncached admin-ajax requesters that created CPU overload. Most of requests were coming from WPDiscuz:

50258     [action] => wpdGetNonce
   3608     [action] => searchwp_live_search
   2746     [action] => wpdShowReplies
   1710     [action] => more_post_ajax
   1136     [action] => wpdReadMore
    536     [action] => more_ugc_ajax
    392     [action] => wpdLoadMoreComments
    280     [action] => heartbeat

It’s a quite visited website that we have, and WPDiscuz ajax requests were coming for every view, so it turned out about 4 uncached requests per second.

After we’ve updated to the latest version today, it went to about 6 per minute which made site usable again, but still quite slow. I believe this is not intended to happen. What would you recommend us to do?
P.S. I don’t know unfortunately how many requests were made before as we haven’t had that issue before and were not tracking that.
Cheers,
Sabrina