"The difference between a Chess player and a Chessmaster, is the Chessmaster looks at the same piece in every possible consideration not to lose before moving."
@ali-pahlawan ... might be because that isn't what I said.
Left operand != Right operand (Value, Numeric, 0.)
....same as.....
Left argument is not equal to Right argument (Value, Numeric, Zero).
This only addresses the origin of your problem with arrow marking errors.
@q8carpenter .... only not equal to zero, with this specifically.
You want your indicator to only mark what is genuinely true.
You forgot to condition the custom indicator.
E.G.: Buy arrow is different than Value, Numeric, zero.
You have the right idea, since most indicators repaint as price has too many influences within how and when.
Indicator must remain present when price no longer influences current candle. We (including I), tend to get too focused, wanting the most perfect entrance and exit - though also consider this reply to revisit managing expectations. We want sincerity within our EA.
Indicator must not be equal to zero (if it was, it would not be there). This is still necessary to meet both methodology and mathematical rules (might also be within rules for coding languages, though I'm not a coder - so I cannot attest).
Hope this provides better insights. Happy trading!