If you have access to the source code of a script, you can add some plots to visualize when the conditions used in 'alertcondition' function are met and when they are not, right on the chart. Below you can see a piece of code that demonstrates how you can do this (this is just an example, you will need to replicate the plots in your specific indicator):

//@version=5
indicator('Simple alert script')
your_condition = close > 50
alertcondition(your_condition, 'Simple alert', 'Now close is bigger than 50')
plot(your_condition ? 1 : 0)

If an alert condition was true (plotted '1' on a sub-chart) on a particular candle, but no alert has triggered (and vice versa), please send us a report from that chart with a screenshot, demonstrating the issue, and the source code. Don't forget to select the 'Alerts' as an issue type and specify the alert with a problem.