It's rare that "I" is used because usually papers have multiple authors, and also the academic community has a weird collective delusion that you have to use "we"... but there are still a reasonable number of papers that use "I".
Established tradition doesn't negate "collective delusion".
And anyone who uses the use of "I" in a paper to imply anything about its authenticity is definitely indulging in some form of a delusion. It's not the norm, but is definitely permitted in most technical fields. When I was in academia no reputable journal editor would take seriously reviewer feedback that complains about the use of I.