The lucky meaning is already in the 付く definition, so this does seem superfluous, but yeah, I presume the exist of conjugations at all is just a mistake or a database error.
I double checked a few Japanese-Japanese dictionaries, and they list is as a regular ichidan verb. One of them also give ついてない as a usage example. So it can certainly be inflected, but not all inflections make sense for all verbs. The inflections given on Jisho are automatically generated, so they should be read as a suggestion that the verb can be inflected, not necessarily that all of those infections are in general use.
That makes sense. Thank you very much!
付いてる
I came across with 付いてる to convey "to be lucky". It is listed as ついています(note the い) in my textbook, and I initially assumed that this is one of those cases where the verb is only used in progressive tenses when conveying this meaning, as is the case with 知っている、持っている、etc. It made complete sense as I understand that it comes from the expression 運が付いている。"to be attached the luck".
However, I found that the entry for this word in jisho.org is 付いてる. It is marked as a 表現, allright. What is so confusing is that you can get all the conjugations and, to my surprise, it was being conjugated in all the tenses as a regular 一段動詞, with conjugations such as ついてています。(double progressive conjugation). I wonder whether I wrongly assumed that this was an expression only used as a progressive tense verb or it is actually a full いちだん verb with the full range of conjugations and uses available. If it's not the latter, could you fix the entry so as not to show misleading conjugations?
Thank you very much.