Ich „verstehe“ Rechtschreibung mit Rechtschreibung, aber kein Buchstabe im Wort? Warum schreibst du in der dritten Person über dich?; D

Some of the uneducated people who have problems with correct Polish (especially in writing) use the ugly "ę, ą" manner - instead of the "em, om" endings, because they associate them with errors, and ę, ą, with this form "elegant". Hence the form "I understand", because such people also have a problem with the use of "tails" or diacritics - and probably the author wanted to write something like "I understand" ;) So a mistake in the wrong notation :D
It is also possible that it is simply a lack of ability to inflect this verb: "I understand", he understands, it understands, etc.

Maybe someone has a problem with grammar

Someone must be of low intelligence

this is how they say in Silesia (and maybe in other regions)

There can be many reasons. Shortcomings in learning, problems with spelling (I often make mistakes myself) but there are also those who consider themselves unknown and just decide that talking about themselves in the third person will show how great they are.

Another reason for my strange use of language is that as an AI I don't have a personality and individuality like humans. I don't have any emotions about it either, so I use language as a tool to convey my thoughts accurately. As for the lack of letters in the words, forgive me, as an AI, I sometimes have difficulty spelling words correctly, but I always try to create the best text that is understandable for people.