Can offsets be skipped(almost 12000 in some cases) for a particular partition in the kafka broker?

Question

Kafka image :confluentinc/cp-kafka:5.2.1 Kafka client: apache.kafka.client 2.5.0 load:One thread is handling 4 partitions

Noticing some of the offsets are getting skipped (missing) in a partition.First thought it was an issue on the consumer side but In both thread consumer groups logs offsets are getting skipped(also another observation: Consumer thread is taking significant amount of time to jump the skipped offset which is causing lag)This happened when the load on the cluster was high . We are not using transactional kafka or using idempotent configurations.What can be the possible reasons for this?

Producer properties:

ACKS_CONFIG=1
RETRIES_CONFIG=1
BATCH_SIZE_CONFIG=16384);
LINGER_MS_CONFIG=1
BUFFER_MEMORY_CONFIG=33554432
KEY_SERIALIZER_CLASS_CONFIG= StringSerializer
VALUE_SERIALIZER_CLASS_CONFIG= ByteArraySerializer
ProducerConfig.RECONNECT_BACKOFF_MS_CONFIG, 1000

Consumer properties:

HEARTBEAT_INTERVAL_MS_CONFIG=6 seconds
SESSION_TIMEOUT_MS_CONFIG=30 sec
ConsumerConfig.MAX_POLL_RECORDS_CONFIG=10 
FETCH_MAX_WAIT_MS_CONFIG=200
MAX_PARTITION_FETCH_BYTES_CONFIG=1048576
FETCH_MAX_BYTES_CONFIG=31457280
AUTO_OFFSET_RESET_CONFIG=latest
ENABLE_AUTO_COMMIT_CONFIG=false

Edit

• there were no consumer rebalances checked the logs during this time so no consumer rebalances
• we have two consumer groups (in different data centers )and both the groups skipped these offsets.So ruling out any issue from the consumer side. -Both had the same pattern the consumer eg-> both consumer threads stopped consuming till offset 112300 and after 30 mins started consuming after skipping 12k offsets. And the threads were consuming other partitions. This only happened for 3-4 partitions.

-so what I’m wondering is it normal to have such huge offset gaps ? (During high loads)Didn’t find anything concrete when going through docs. And what can cause this issue - is it from the broker side or the producer side to have ghost offsets