Cannot recover from backup file

The Signer Engine cannot read the backup after a restart.

Nov 29 11:34:50 ubuntu ods-signerd: [engine] signer started
Nov 29 11:34:50 ubuntu ods-signerd: [file] open file file=bellgrim.se.backup mode=reading
Nov 29 11:34:50 ubuntu ods-signerd: [keys] add locator 71ac174fbb11cd54a49678f861ef74ef
Nov 29 11:34:50 ubuntu ods-signerd: [keys] add locator 952f1f004e443d8dfb9015dd51a03ced
Nov 29 11:34:50 ubuntu ods-signerd: [domain] +DOMAIN: bellgrim.se.
Nov 29 11:34:50 ubuntu ods-signerd: [rrset] +RRSET: <bellgrim.se,DNSKEY>
Nov 29 11:34:50 ubuntu ods-signerd: [rrset] +RR: bellgrim.se. 3600 IN DNSKEY 257 3 8 AwEAAbx6sLDEZzVswkJMjW54EaBfWyOWArbsEpco9wdvIwz0p9qlEy6gOZI1YcANIFF1MRm1ogJ6zOBotRY20fdFOZQV6uHyL5aYxjfx9mjzmY6U2jeSJeWWWvNP003s6vSU3l0wTI3+VagIOLP6F14ezssIliW7PmDY85ED47B+MWwyvI714Mc4/QKH1qQKvHjzb8jrzg8ns25Kxv2AGcVdHd3JbiuStAUZuPVIVIKbfQ6w92s3g+LcV6VHSZBj/kccbSeoueKNbgU40QnQOAuG6zCd8KVx8dxP5n8mfl/EWP0BhUE4qyGV2CF9/Yv9g753X3jwk4OJq5Y5x/D1BfSRt9E= ;

{id = 56176 (ksk), size = 2048b}
Nov 29 11:34:51 ubuntu ods-signerd: [rrset] +RR: bellgrim.se. 3600 IN DNSKEY 256 3 8 AwEAAbqRm5AHsc66MX7s+kjdfBROidBA3ygZ8zMUiKynZvaBwJTSvmP15Zc5mur+cq4o1ECKSF1WGsq/NiKM0q3tvWNq4beEmJopOLj3vF75gqTxqaVKu6WjtP6+2d05LyBSJmZ6LDe8R656xgQFpfGslitSpDujUi1M7sBxuKGPH+5l ;{id = 55018 (zsk), size = 1024b}
Nov 29 11:34:51 ubuntu ods-signerd: [file] open file file=bellgrim.se.inbound mode=reading
Nov 29 11:34:51 ubuntu ods-signerd: [file] unable to open file bellgrim.se.inbound for reading: No such file or directory
Nov 29 11:34:51 ubuntu ods-signerd: [zone] unable to recover zone bellgrim.se: corrupted file
Nov 29 11:34:51 ubuntu ods-signerd: [rrset] -RR: bellgrim.se. 3600 IN DNSKEY 257 3 8 AwEAAbx6sLDEZzVswkJMjW54EaBfWyOWArbsEpco9wdvIwz0p9qlEy6gOZI1YcANIFF1MRm1ogJ6zOBotRY20fdFOZQV6uHyL5aYxjfx9mjzmY6U2jeSJeWWWvNP003s6vSU3l0wTI3+VagIOLP6F14ezssIliW7PmDY85ED47B+MWwyvI714Mc4/QKH1qQKvHjzb8jrzg8ns25Kxv2AGcVdHd3JbiuStAUZuPVIVIKbfQ6w92s3g+LcV6VHSZBj/kccbSeoueKNbgU40QnQOAuG6zCd8KVx8dxP5n8mfl/EWP0BhUE4qyGV2CF9/Yv9g753X3jwk4OJq5Y5x/D1BfSRt9E= ;{id = 56176 (ksk), size = 2048b}

Nov 29 11:34:51 ubuntu ods-signerd: [rrset] -RR: bellgrim.se. 3600 IN DNSKEY 256 3 8 AwEAAbqRm5AHsc66MX7s+kjdfBROidBA3ygZ8zMUiKynZvaBwJTSvmP15Zc5mur+cq4o1ECKSF1WGsq/NiKM0q3tvWNq4beEmJopOLj3vF75gqTxqaVKu6WjtP6+2d05LyBSJmZ6LDe8R656xgQFpfGslitSpDujUi1M7sBxuKGPH+5l ;

{id = 55018 (zsk), size = 1024b}

Nov 29 11:34:51 ubuntu ods-signerd: [rrset] -RRSET: <bellgrim.se,DNSKEY>
Nov 29 11:34:51 ubuntu ods-signerd: [engine] unable to recover zone bellgrim.se from backup, performing full sign
Nov 29 11:34:51 ubuntu ods-signerd: [engine] commit zone list changes