I'm monitoring a log file using item key log (not logrt).
Modified the last modification time using touch command, the file has been read again from start of the file.

This causes version after 2.0.13, 2.x and 3.x.
Not causes in 2.0.8.

This described in online manual, top of "Important notes" in "6 Log file monitoring".
"Do not modify the last modification time of log files with 'touch' utility, " for "last modification time (for logrt)".
This sentence looks without key "log".