Do you have any grounds for this statement whatsoever? Sounds a lot like baseless speculation. How would you imagine that FBI bypasses the end-to-end encryption?

The meta data of who talks to who is not encrypted.

Edit: This is the whole problem tin-foilers have with Signal being the sole operator of servers and not allowing for federation.

plain old fashioned MITM with a court order accompanied by a gag order should be sufficient.

Remember WhatsApp is BOTH the PKI infrastructure and the and the message transmitter. It is trivial for them to MITM by sending you and the recipient a different public key that they control and intermediate.

The encryption prevents OTHERS from snooping on you. It doesn't protect you from WhatsApp itself - or the government acting with a warrant.