The node links of each node are built using a lazy loader. Which means they are not cached and need to be rebuilt on every page.
On a default article node, that is about 10% of the whole processing time, mostly because of comment.module. Note that this also happens when e.g. displaying a teaser of 20 nodes on the frontpage.
The main reason this was done is that those links are often related to specific permissions and are sometimes not cacheable well. However, when we did this, we didn't have the cache context bubbling and other tools that we have now.
#2530846: Fix and improve comment cache tag usage → makes comment links cacheable, the only remaining problem then are statistic counters. See that issue for some discussion on that, still need to take it over to this.
Remove the lazy builder, build node links directly. Figure out what to do with statistics view counters.
Fixed
8.0 ⚰️
node system
It affects performance. It is often combined with the Needs profiling tag.
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It's likely this issue predates Contrib.social: some issue and comment data are missing.