Hello,

if you have 2 items dependent on the same master item and a trigger with expression that uses last functions to compare values from these 2 dependent items, you may get a flapping problem (instantaneous recovery), because dependent items are not updated in a single take.

 

[Example]

We have:

master item: {"valueA": 1, "valueB": 1}

dependent itemA: 1

dependent itemB: 1

trigger with expression: last(//itemA)<>last(//itemB)

We receive update:

master item: {"valueA": 5, "valueB": 5}

dependent items get updated one after another

 

Expected behaviour:

No problem is received because 5 == 5.

 

Actual behaviour:

Problem created because one of the dependent items got updated first, which triggered recalulation of trigger expression, where 5 != 1.

Shortly after - at the same second - the other dependent item gets updated as well, now 5 == 5 and the problem gets resolved.

 

Workaround:

Use min(//itemA,5s)<>min(//itemB,5s)