I am getting some interesting results using tag history LastValue aggregation mode while allowing interpolation. Here is a screenshot of the database query for the tag.
As you can see, there is a value of 0 recorded on 03/23/2020 around 7:30pm and the next value comes in the next day at 9:50 am. Now, when we query the tag history using a 1 minute interval with interpolation enabled, we get the following result.
It looks like the interpolation is continually accumulating a value for that tag. I would expect for the interpolation to continue to simply use the last known value recorded in the DB. Am I miss interpreting this or is there another way to achieve what I have described?