The SQL Server error log contents in SSMS (SQL Server Management Studio) and in the Foglight Error Log panel are different than the alarm displayed in the Alarms dashboard and those fired from Foglight. This is taking cleared and historical alarms into consideration.
In 2013 as part of Enhancement SSDB-9413 a mechanism was added to the SQL Server cartridge to files the Error Log messages to show only one error of the exact same message in one iteration.
The improvement was done in both of these alarms
The data of the topology is collected every X seconds and the alarm is fired once every five minutes and collects all of the errors of the last X minutes. Therefore, there some alarms that would look the same. The enhancement creates only one alarm instead of multiple alarms of the same type.