I got this issue while using ADRCI tool to maintain the logs. This is how I fixed it:

[[email protected] ~]$ adrci

ADRCI: Release 11.2.0.3.0 - Production on Wed May 31 09:43:29 2017

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ADR base = "/u01/app/oracle"
adrci> show homes
ADR Homes: 
diag/diagtool/user_oracle/host_3933716914_11
diag/clients/user_oracle/host_3933716914_11
diag/rdbms/dbinst/DBINST
diag/tnslsnr/dbserver/listener
adrci> set home diag/diagtool/user_oracle/host_3933716914_11
adrci> purge
DIA-48322: Relation [INCIDENT] of ADR V[2] incompatible with V[2] tool
DIA-48210: Relation Not Found
DIA-48166: error with opening ADR block file because file does not exist [/u01/app/oracle/diag/diagtool/user_oracle/host_3933716914_11/metadata/INCIDENT.ams] [0]

adrci> migrate schema
Schema migrated.
adrci> purge
adrci> quit