Calc: Why is a <~> impossible to delete?

In '=quotient((sum(j18:p18 ~4); I have removed & replaced the TILDA many times.
The prgm puts it back … WHY?

And, could this cause Err 502 [invalid argument?

Thanks …

What about the closing bracket after P18? I mean =QUOTIENT(SUM(J18:P18);4)

Quoting @abi: “…replaced the TILDA many times…”
By what?
(If you do many times exactly the same with a software, it should answer many times in exactly the same way. That’s what we expet ordinary software to do.)
Quoting @abi: “And, could this cause Err 502 [invalid argument?”
Yes. of course! (What’s the orphaned [ meant to mean?)

From the help:
Invalid argument Function argument is not valid.
For example, ...

Quoting @Lupp from Calc: formula: why are tildes auto-replacing commas?

The tilde is (as @pierre-ives samyn states correctly) the union operator for ranges in syntactically correct expressions. It is, however, also a kind of error marker in cases where parameter delimiters cannot be interpreted correctly because of rotten syntax.

Instead of starting with =quotient((, it should look like this instead, as @JohnSUN wrote.