PFEMAN session-IDs are not in sync with the BFD session IDs of RE, 
This PFEMAN logs are pfe level debug logs triggerred for the BFD session id “xxx” flap.
The bfd session with peer flapped and from the detail and extensive output of bfd sessions, 

"Session up time 06:51:30" >> There is an uptime in this line, it means session was deleted and created again, hence session id was changed from “xxx” to “yyy”.

 There will be no any service impact, Any BFD flap would trigger the above PFEMAN logs along with the session ID.

++++++++++++++Logs+++++++++++++++

%PFE-3: fpc2 PFEMAN: session id 759 with version-id 0xfffffffe went down at 01:05:15.816154
%PFE-3: fpc0 PFEMAN: session id 759 with version-id 0xfffffffe went down at 01:05:15.852601
%PFE-3: fpc3 PFEMAN: session id 759 with version-id 0xfffffffe went down at 01:05:15.852801
%PFE-3: fpc4 PFEMAN: session id 759 with version-id 0xfffffffe went down at 01:05:15.852063
%PFE-3: fpc1 PFEMAN: session id 759 with version-id 0xfffffffe went down at 01:05:15.852143

Mar 26 01:05:15 bfdd[10643]: %DAEMON-4-BFDD_STATE_UP_TO_DOWN: BFD Session 172.27.3.155 (IFL 666) state Up -> Down LD/RD(245/162) Up time:23:24:48 Local diag: CtlExpire Remote diag: None Reason: Detect Timer Expiry.

Mar 26 01:05:15 bfdd[10643]: %DAEMON-4-BFDD_TRAP_SHOP_STATE_DOWN: local discriminator: 245, new state: down, interface: xe-2/2/5.121, peer addr: 172.27.3.155

Address         State   Interface   Time   Interval Multiplier

172.27.3.155       Up    xe-2/2/5.121  0.900   0.300    3  

 Client OSPF realm ospf-v2 Area 0.0.0.0, TX interval 0.300, RX interval 0.300

 Session up time 6d 20:06:07, previous down time 00:31:33

 Local diagnostic None, remote diagnostic None

 Remote state Up, version 1

 Replicated 

 Session type: Single hop BFD

 Min async interval 0.300, min slow interval 1.000

 Adaptive async TX interval 0.300, RX interval 0.300

 Local min TX interval 0.300, minimum RX interval 0.300, multiplier 3

 Remote min TX interval 0.300, min RX interval 0.300, multiplier 3

 Local discriminator 245, remote discriminator 162

 Echo TX interval 0.000, echo detection interval 0.000

 Echo mode disabled/inactive

 Remote is control-plane independent

 Session ID: 0x2f7-----> convert this value to decimal 759 which is in logs of PFEMAN

These PFEMAN logs are nothing but PFE level debug logs which will be generated whenever BFD session flaps, and it has no impact and just informational logs.

Make sure, that bfd session-id value is same in PFEMAN and bfd extensive outputs taken.