MediaWiki version: 1.36.0-wmf.16
Use of Language::formatNum with a non-numeric string was deprecated in MediaWiki 1.36. [Called from Language::formatNum]
1 of these seen since deploy of 1.36.0-wmf.16.
Another formatNum deprecation notice. At the moment I'm assuming this is low-impact and at this stage won't block the 1.36.0-wmf.16 train (T263182) on it unless it becomes noisier, but I would very much like to see all of these resolved soon. They will quickly accumulate into a real problem for production error triage.
This is happening when Lua code in Scribunto calls core's formatNum with a NaN double value. (Could also happen for positive or negative infinities as well, but all the examples I've looked at have been NaNs.)