According to Update 1.86, in changelog it can been seen that bipod of LMG Zafir have been tweaked since they were too short.
Visuals:
Tweaked: The legs of Zafir’s bipod were too short.
When player is prone, bipods are still too short.
https://steamuserimages-a.akamaihd.net/ugc/945090764932882197/AF35269EE15DED8DC953DFFDD8DA2C13A4F4B9F3/