Is this correct in American English: It has helped me developed

I've come across a brief overview about a Canadian sales representative that says :

I grew-up in a family business specializing in short-term rental accommodations. Our resort, Tyrolean Village Resorts, was built by my father and uncle in the 1960’s and is now managed by my brother and I. This unique experience has helped me developed my 15-year real estate career in selling and buying short-term rental accommodations and working through the requirements to establish and operate such properties in the area.

I've noticed that he used "present perfect and past simple at the same time" ( has helped me developed ).'

Question:

I'm wondering, what is the grammar rules used here? and if I were to change it to "has helped me develop", would the meaning change?

The sentence as written is simply incorrect. The object of "help me" should be an infinitive. As you stated, "has helped me [to] develop" would be one way of correcting the sentence.

This is the same regardless of what tense the first verb is in. "helped me develop," "will help me develop," "would have been helping me develop," etc. are all correct phrases.

Alternatively, you could use simple past tense in a separate prepositional phrase: "has helped me as I developed my career." In this case, "me" becomes the object of "helped" and the author is stating that he developed his career in the past. In that case, however, I would also change the first part to simple past tense as well, implying that the help and the career development both took place in the past: "this experience helped me as I developed my career."

https://en.m.wikipedia.org/wiki/Uses_of_English_verb_forms#Bare_infinitive