Steps to replicate the issue (include links if applicable):

• This does not work: https://en.wikipedia.org/w/api.php?action=query&format=json&list=abuselog&afllogid=30840290&aflprop=ids|filter|user|title|action|details|result|timestamp|hidden|revid
• This does work: https://en.wikipedia.org/w/api.php?action=query&format=json&list=abuselog&afllogid=30840290&aflprop=ids|filter|user|title|action|result|timestamp|hidden|revid

What happens?:

The first query is truncated (essentially empty) with a warning of "This result was truncated because it would otherwise be larger than the limit of 12,582,912 bytes."

(Just to be clear, the above query will also fail for aflprop=details alone.)

What should have happened instead?:

It should be possible to fetch the log ID.

It seems likely that the configured size limit is too low relative to actual log data.

Notes:

• It is possible to view the log on the website at https://en.wikipedia.org/wiki/Special:AbuseLog/30840290, but this issue makes scripting much more difficult. The log details are required if you are trying to do any kind of analysis of abuse filter logs.
• This is just one example ID. It's an issue querying the logs for pretty much any filter on English Wikipedia.
• There are many filter IDs where it's difficult to fetch more than a few log entries at a time.

Software version (on Special:Version page; skip for WMF-hosted wikis like Wikipedia):

Other information (browser name/version, screenshots, etc.):

The issue happens for any user agent.