LiteSpeed 8.8 Log Backup job Hangs

SQL Agent job created using the Litespeed 8.8 Wizard.

The job is for log backups of all 'USER' databases. Runs every 15 minutes.

Job is as follows:

declare @script nvarchar(4000)
set @script = N'
exec master.dbo.xp_backup_log
@MultiDatabaseType = N''USER'',
@progressname = N''dfd619be-cc9d-48ba-9412-1f546f50f912'',
@backupname = N''%DATABASENAME% - Transaction Log Backup'',
@desc = N''Transaction Log Backup of %DATABASENAME% on %Y-%m-%d %I:%M:%S %p'',
@compressionlevel = 2,
@filename = N''X:\DD301Server\TrxnLogBackups\%D_%T_%z.bak'',
@init = 1,
@OLRMAP = 1 ,
@with = N''STATS = 10'''
exec (@script)

/**LiteSpeed Data. Do not modify.**/
Normally, all is well and all the desired log backups are created.
Approx once per week, the job hangs. By 'hangs' I mean, the job shows running, but no log backups are created. At the same time as the failure a '.lsm' file is written to the destination folder for the backups.
After the failure, the SQL Agent job fails to run (because it continues to show 'running' in wont start).
What is going on here?
What to do with the .lsm file?