How to parse timestamp & other fields in logs with no timestamp?

[Sid]

log sample
[6724268.575s][debug][gc,age] GC(10561) Desired survivor size 33554432 bytes, new threshold 1 (max threshold 15)

I am getting timestamp parsing errors for the above source logs

using below props

DATETIME_CONFIG = CURRENT

LINE_BREAKER = ([\r\n]+)

SHOULD_LINEMERGE = false

TRUNCATE = 999999

TZ = America/New_York

[richgalloway]

Splunk should not be trying to find a timestamp when DATETIME_CONFIG=CURRENT is used.  Perhaps, however, the TZ setting is overriding that.  Try removing the TZ setting.

[Sid]

previously i had only DATETIME_CONFIG=CURRENT but i was still getting timestamp parsing error in data quality dashboard , so i added TZ later.