The two birthdays mentioned here are both references to Trish's ambiguous birthday in canon. Both two birthdays were stated in different sources.
Team Bucciarati, currently escorting Trish.It's April 19th, isn't it?No, it's June 8th, right?Whoa.A sudden brake.*screeech*Sorry Trish.No... This is really an accident...You really are a sly one. Using the sudden brake as an excuse to dive into my boobs.Come on, guys! The least you can do is actually remember my birthday.