Sendmail eats CPU on r317039

On a recent kernel sendmail is constantly consuming CPU.

truss -p PID

shows:

sendto(3,"<22>Apr 17 10:30:33 sendmail[362"...,163,0x0,NULL,0) ERR#55 'No
buffer space available'
nanosleep({ 0.000001000 }) = 0 (0x0)
sendto(3,"<22>Apr 17 10:30:33 sendmail[362"...,163,0x0,NULL,0) ERR#55 'No
buffer space available'
nanosleep({ 0.000001000 })
...

This is on an arm64 system