while working at a Fortune 500 MNC, gig before this one, I used to get LinkedIn hits from recruiters.

never got serious ones before, the occasional, useless headhunters who are clearly not based in the same country, but these were different. They were big companies in Canada, ones I'd definitely heard of and even applied to in the past. They were direct, were recruiters for those companies themselves, and were plugged in, able to answer questions, and engaging.

they constantly sent job ads, but only via .pdf files. I even pushed back on one and said I don't open random pdfs, send me a link and they declined. Same recruiter hit me up for a similar role a month later, also via pdf.

Multiple other members of the IT org, esp. the security and infra teams, also reported similar, aggressive recruitment efforts with pdfs. This was around 2020-2021.