I'm unable to read some threads, as they appear blank to me.
Here is my latest example of it:

The thread seems to have quite a lot of success:

This issue keeps popping, it is not the first day, and I believe not the first thread, although I don't remember other titles.
I obviously tried to reload the page and tried the page on different sessions, after having disconnected and closed my browser.
I believe I haven't had any issue with any other thread this week.

Have a nice day

To me it looks like the root cause of this issue is that the URL to the last unread post in a thread can get messed up if that post was deleted.  Normally something like "?page=1#post-361403" will be appended to the topic URL in your browser in order to advance the page to the last post that you haven't read, but the page/post reference may be invalid if someone deleted that post.  It looks like the current workaround is to delete the ? and everything after it in the URL for the topic, and the thread will display as normal.  @raspberly or @Sobert or another G2G admin may be interested in this little detail regarding this bug.

No problem.  Regarding the "City Centres" topic, that one is 7 months old and there could have definitely been 215 spam posts in that amount of time given how much bot activity we get around here and the fact that the bots tend to congregate in the same topics.  So I believe the odds are low that you're missing out on any content that's actually worth reading.