Some params messed up with IFS and pandas==2.3.3

[williamhobbs]

I've been using :2t:sfc: as a search string for 2m temperature in IFS. But with the latest version of Herbie (2026.3.0) and pandas 2.3.3, that isn't working for some reason. The search_this example has some extra 'nan' values inserted, :2t:nan:sfc:nan:g:0001:od:fc:oper:

Upgrading to pandas 3.0.2 fixes it:

Might be related to 523 #518? (edit: I referenced the wrong other issue...)

[williamhobbs]

I thought that some params where showing up normally, but I was wrong. Looks like they all have nan in there....

[williamhobbs]

sorry, closed the wrong issue...