Failed to read a certain GTID_EVENT , which has event length as 2e

We have a client application to read from the mariadb binary log on MariaDB server version 10.11.5-MariaDB-log.

We started getting below error on trying to ready the mariadb binlog event,

Failed to replace GTID event with backwards-compatible event: corrupt event.; the first event 'archive_mysql.005039' at 16814957, the last event read from 'archive_mysql.005039' at 16814957, the last byte read from 'archive_mysql.005039' at 16815003.

1)
The application works fine with all other GTID_EVENT "START TRANSACTION", but problem is there in reading only this particular event with length 2e. This event has come only once per binlog. Below is that event,

1. at 16814957
   #240314 17:59:51 server id 1 end_log_pos 16815003 CRC32 0x81e297df
2. Position

3. Timestamp

   Type

   Master ID

   Size

   Master Pos

   Flags

4. 100936d |17 3b f3 65 |a2 |01 00 00 00 |2e 00 00 00 |9b 93 00 01 |08 00
   #
5. 1009380 38 94 2d 0b 00 00 00 00 00 00 00 00 0a 96 9e 61 |8.-............a|
6. 1009390 04 00 00 00 00 01 ff df 97 e2 81 |...........|
   #
7. Event: GTID 0-1-187536440 cid=73506454
   /Unable to render embedded object: File (100001 SET @@session.gtid_seq_no=187536440*//*) not found./;
   START TRANSACTION
   /!/;

There is no problem reading other GTID_EVENT "START TRANSACTION" event as given below,

1. at 17157329
   #240314 18:00:02 server id 1 end_log_pos 17157373 CRC32 0xd95a7577
2. Position

3. Timestamp

   Type

   Master ID

   Size

   Master Pos

   Flags

4. 105ccd1 |22 3b f3 65 |a2 |01 00 00 00 |2c 00 00 00 |fd cc 05 01 |08 00
   #
5. 105cce4 5c 96 2d 0b 00 00 00 00 00 00 00 00 0a 1e af 61 |\.-............a|
6. 105ccf4 04 00 00 00 00 77 75 5a d9 |.....wuZ.|
   #
7. Event: GTID 0-1-187536988 cid=73510686
   /Unable to render embedded object: File (100001 SET @@session.gtid_seq_no=187536988*//*) not found./;
   START TRANSACTION
   /!/;

So far we are unable to understand the nature of this GTID_EVENT that has 2e length and what could cause this event to appear in the binlog. Can you please provide some information regarding the nature of the event and how does it appear in the binary log.
Attaching the binary log 5039 , that has the binlog event GTID_EVENT in question at offset 16814957. Also Attaching the output "show variables" command to get the db configurations.

1.1) What exactly is this GTID_EVENT with length 2e ?
1.2) How to get this GTID_EVENT in the binlog ?

2) On searching over , there are two issues reported related to this,

https://jira.mariadb.org/browse/CONC-650
https://jira.mariadb.org/browse/MDEV-5754

But not none of them seems same. The CONC-650 seems related to XA transactions and MDEV-5754 fixed in 10.0.9. The version we are using is 10.11.5.

In CONC-650 , it is suggested to set the mariadb_slave_capability to 4 , which I understand it MARIA_SLAVE_CAPABILITY_GTID. After setting the mariadb_slave_capability to 4, the client application is receiving that GTID_EVENT properly , without any problem. But we are not certain what would be the implications of setting this capability.

2.1) What is the default capability of the slave application ?
2.2) What are the effects of setting mariadb_slave_capability to 4 ? Could there be a problem somewhere , in some scenarios ?