I have just join vs I have just joined

Some examples from the web:

• I may have just auditioned to join them.
• I must just join that wonderful young artist over there.
• I didn't just join a firm.
• I will do it, just join my team.
• And if you guys would just join hands, close eyes and concentrate.
• Maybe we should just join them.
• I'm not asking you to just join the team.
• You'll just join Emmett a hundred days later.
• No. Just join us, please.
• In my dreams, you just join...
• I was trying with the second adapter but if I could just join -
• I was trying with the second adapter but if I could just join -
• I'll just join a dodgeball league for lonely men whose wives won't do stuff to make them happy.
• In my dreams, you just join in - ooh. Okay.
• Now, let's just join hands, and recite the Serenity Prayer.
• Maybe you could stay and just join me for like one drink.
• did you just join the Navy?
• You should just join us, and I could totally change the reservation for three.
• Let's let these guys run with this, and then you can just join up after you testify.
• Let's let these guys run with this and then you can just join up after you testify.

Some examples from the web:

• Mr President, I know I have just joined you, but I have been watching the monitor at a very important group meeting and I just wonder why we are not going seriatim.
• I haven't just joined, you know.
• I haven't just joined, you know.
• Have I just joined a cult? No.
• Now they have just joined the defense team of the Jackson Hale trial.
• Galen Tyrol and Samuel Anders have just joined Saul Tigh in the airlock.
• Mr Humphreys just joined our maths department.
• You just joined the losing team.
• Iraqi patrol just joined the party.
• Because her mother just joined Scientology.
• This has created an anomalous situation in which third country workers have more freedom to move within the EU than those of the countries which have just joined.
• Among these are the new countries which have just joined the European project and which are among those suffering the most.
• In the countries that have just joined us, average gross domestic product per capita is equal to only 45% of the average in the Fifteen.
• It is my duty and the duty of the Commission to represent the general interest of Europe, particularly those Member States who have just joined our Union.
• Chip just joined Dad's practice after his surgical residency, following in the great man's footsteps.
• She just joined, like, a week ago.
• We've just joined with Marquis De Montcalm's mercenary force to repel the 43rd Highland Regiment.
• Look at that, two painted ladies just joined in.
• My partner didn't show, and your new client just joined the club.
• Commander Boles, the president just joined us.