Update 2.3.4_1-> 2.4.0 -> broken ospf over gre[SOLVED]

[vizavi]

Hello

After update 2.3.4_1-> 2.4.0  ospf over gre looks broken

#site1 ( 2.3.4_1 )
logs
Nov 4 09:47:58 ospfd 45632 Packet[DD]: Neighbor 10.10.10.18 MTU 1400 is larger than [gre1:10.10.10.25]'s MTU 1376
Nov 4 09:47:53 ospfd 45632 Packet[DD]: Neighbor 10.10.10.18 MTU 1400 is larger than [gre1:10.10.10.25]'s MTU 1376
Nov 4 09:47:48 ospfd 45632 Packet[DD]: Neighbor 10.10.10.18 MTU 1400 is larger than [gre1:10.10.10.25]'s MTU 1376
Nov 4 09:47:43 ospfd 45632 Packet[DD]: Neighbor 10.10.10.18 MTU 1400 is larger than [gre1:10.10.10.25]'s MTU 1376

#site2 ( updated to 2.4.0 ) <- ospf broken
#route
10.10.10.25 link#12 UH 2322 1376 gre2

#logs
Nov 4 16:50:04 ospfd 52879 *** sendmsg in ospf_write failed to 224.0.0.5, id 0, off 0, len 64, interface gre2, mtu 1400: Permission denied

It looks like site2 after upgrade it not sending correct MTU info to it peer on site1
GRE header ignored may be .

Please advice .

[Wordo]

Can you try adding a floating rule for this?

[vizavi]

workaround was :

MTU settings for GRE interfaces
new 2.4 version MTU 1376
old 2.3.4 version MTU 1400

in this case
old<–> old <--working
old<--> new <--working
new<--> new <--working