After Rachel and Phoebe see Bonnie and Ross in Central Perk, Rachel is yelling at Phoebe that she needs to break them up. At first, Phoebe is holding her coat in her left hand and a purse in her right, but then she is holding them both in her left, with no time to have changed hands.
When Chandler's boss is slapping all the guys on the butt, on the side of the table closest to the camera there is a notepad with a pen on it. When the guy comes back in to get his briefcase, the pen is no longer there.
At the end of the episode Monica says a wrestler goes to Iran for training and pulling off thieves' arms. Iran doesn't have this rule. This rule only is used by Sonni and Wahhabi Governments, not Shia. Iran has a Shia government which is opposed to these sort of violence.
Phoebe is a vegetarian but towards the end when they are grilling food while watching Pete's fight she is seen getting a hamburger bun prepared and taking what is clearly a meat burger from Ross off the grill.
In Pete's third fight he is kicked in the groin multiple times. Groin strikes are illegal in UFC so Pete would have signaled for the referee to stop the fight.
Pete's opponent in his first UFC fight is Tank Abbott. At this point in his career, Abbott was a headliner; it is unlikely he would be matched against someone making his debut.
Bonnie could not have grown her hair from bald to as long as shown in only 2 years.