No comments loading on posts from other instances communities subscribed to on my instance?

edit - The problem seemed to be with lemmy.ml being overloaded. When I joined communities there, it didn't immediately say joined, it said join pending. I had to wait a while, then leave and rejoin. Once I did this comments started to flow.

Created a lemmy instance. I can search for and subscribe to other communities (for example, this one). I can see posts from the other communities within my instance when I browse subscribed or all. But none of the posts have comments, they all show as 0, including if I open the post.

I can go direct to that instance and see the posts have comments.

Is this a configuration issue? Thank you -

Edit:

It seems the issue is only with comments on lemmy.ml. I subscribed to some communities at a few other instances and comments are arriving for those communities.

In my log, I see the following related to lemmy.ml comments:

2023-06-06T16:16:29.238969Z ERROR HTTP request{http.method=GET http.scheme="https" http.host=lemmy.dupper.net http.target=/api/v3/ws otel.kind="server" request_id=1e1940f5-6155-49fb-9802-d23ea4253e98 http.status_code=101 otel.status_code="OK"}: lemmy_server::api_routes_websocket: couldnt_find_object: Object was not found in database
   0: lemmy_apub::fetcher::search::search_query_to_object_id
             at crates/apub/src/fetcher/search.rs:17
   1: lemmy_apub::api::resolve_object::perform
           with self=ResolveObject { q: "https://lemmy.ml/comment/460747", auth: None }
             at crates/apub/src/api/resolve_object.rs:21
   2: lemmy_server::root_span_builder::HTTP request
           with http.method=GET http.scheme="https" http.host=lemmy.dupper.net http.target=/api/v3/ws otel.kind="server" request_id=1e1940f5-6155-49fb-9802-d23ea4253e98 http.status_code=101 otel.status_code="OK"
             at src/root_span_builder.rs:16

No idea if this is an issue on my end or not. Any advice appreciated!

Edit - Unsure if related. The non-working lemmy.ml communities all show as "subscribe pending". The other non lemmy.ml communities I've subscribed to that are working all shows as subscribed. I had googled subscribe pending earlier and found some recent posts saying this could be ignored, so I paid it no mind.