Can anyone help me understand how the Latter Rain movement misuses Joel 2:23 (and 23-29)?

for those who don’t know, the latter rain movement was a movement from the 1940s with roots in Pentecostalism.

They taught a lot of false things like how believers can become “manifest sons of God” and be able to relocate on command, speak any language they want, be immortal with their bodies, etc etc… basically think of like, how a lot of modern NAR stuff sounds.

They use the prophecy of Joel 2 to try and “prove” that there will be both a former rain (pentecost) and latter rain (pentecost 2.0 before Christ’s return).

Can someone break down how they’re misinterpreting this prophecy?