hi

yes it will break the chain.

t-log backup job failure break t-log chain

below are different reason,

1st if any one taken full backup of same database where t-log job is running,in this case u want take full backup dont want to break chain of t-log then use copy_only backup

2nd if anyone change recovery model of database

3.if someone executed backup log with truncate_only

in this case you can use trace flag 3031 ,3231 it wont break t-log backup chain