I faced with that errors our 12c database. With those errors MRP process has been stopped at standby database and GAP started to increased

Complete errors are:

Reading datafile '/xxx/datafile/ts_1.dbf' for corruption at rdba: 0x08d6e9fd (file 35, block 1501693)
Reread (file 35, block 1501693) found same corrupt data (logically corrupt)
Sat Jan 18 17:43:50 2020
ERROR: ORA-00756 detected lost write of a data block
Slave exiting with ORA-756 exception
Sat Jan 18 17:43:50 2020
Errors in file /u01/app/oracle/diag/rdbms/sid/sid/trace/sid_pr01_74757.trc:
ORA-00756: recovery detected a lost write of a data block
ORA-10567: Redo is inconsistent with data block (file# 35, block# 1501693, file offset is 3711934464 bytes)
ORA-10564: tablespace TS
ORA-01110: data file 35: '/xxx/datafile/ts_1'
ORA-10561: block type 'TRANSACTION MANAGED INDEX BLOCK', data object# 102109
Sat Jan 18 17:43:50 2020
Recovery Slave PR01 previously exited with exception 756

Here are the solution steps:

1. Start Rman backup for related files at Primary database

rman target /
run
{
ALLOCATE CHANNEL ch1 DEVICE TYPE DISK format '/backup/datafile35_%U.rman';
backup datafile 35;
}

2. Copy rman backup to standby server
scp datafile35* oracle@xxx://tmp/helios
3. At Standby db stop apply

SQL>ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;

4. Catalog and restore backup at Standby db

oracle@server_name/tmp> rman target /

Recovery Manager: Release 12.1.0.2.0 - Production on Sat Jan 18 18:09:52 2020

Copyright (c) 1982, 2014, Oracle and/or its affiliates. All rights reserved.

connected to target database: SID (DBID=7223103652, not open)

RMAN> catalog start with '/tmp/helios';

using target database control file instead of recovery catalog
searching for all files that match the pattern /oradata/gunes

List of Files Unknown to the Database
=====================================
File Name: /tmp/helios/datafile35_v6uma9kg_1_1.rman

Do you really want to catalog the above files (enter YES or NO)? Yes
cataloging files...
cataloging done

List of Cataloged Files
=======================
File Name: /tmp/helioss/datafile35_v6uma9kg_1_1.rman

RMAN> restore datafile 35;

Starting restore at 18-JAN-20
using channel ORA_DISK_1
using channel ORA_DISK_2

channel ORA_DISK_1: starting datafile backup set restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_DISK_1: restoring datafile 00035 to /xxx/datafile/ts_1.dbf
channel ORA_DISK_1: reading from backup piece /tmp/gunes/datafile35_v6uma9kg_1_1.rma
channel ORA_DISK_1: piece handle=/tmp/gunes/datafile35_v6uma9kg_1_1.rman tag=TAG20200118T175944
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:04:45

5. Start apply at Standby db

SQL>ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION; 
Finished restore at 18-JAN-20