I always order Popular Problem.

No, I speak Arabic and it's not so much misspelling as like, lack of sufficient punctuation. Then that is directly thrown into a translator. I'll use the word مشكل as an example and try to explain why the menu says 'Tuna is a problem'. As letters, from right to left, they are l:

m - م (the first letter on the right)

sh - ش

k - ك

L - ل (last letter on the left)

I know those standalone letters look different but that's how they are when they're not conjoined to other letters.

Anyway the problem is that that word can be read multiple ways because a lot of the vowels in Arabic come from small modifiers that no one can be bothered to type out because we know how to infer the pronunciations in context. So let's get into the conflation of the word here. Without any vowels, theoretically the word can be read as mshkl. One way to read the word مشكل can be MuSHaKKal, and with the modifiers it would look like so:

مُشَكْل

It's not easy to see but the first 3 letters have modifiers that make them be pronounced as 'Mu', 'Sha', 'K~', 'Al'. Pronouncing the word this way means 'mixed' i.e. the dish being served is Mixed Tuna AKA Tuna salad.

Now without the modifiers the word can be read as: مشكِل

Now theres no modifier on the second letter so it kind of just blends into the first, becoming pronounced as 'Mush', 'Kill', or 'mash', 'kal'. This word literally translates to 'problem'. And if you just put a noun before problem, it makes sense grammatically to infer that the noun is the problem. Ergo,

"Tuna is a problem". Also known as Tuna salad.