vue-js button element with no type --> submit - vue.js

Question

We have been having a very strange problem in a vue-js (#vue-cli, Build version) application. There was a button in App.vue that had an onclick
<button #click="goIRList" id="irlistBtn">IR List</button>
that was working for fine for some users, every time, and not others. For the others, I checked (with alerts) that the goIRList code was not reached at all. These others had this issue with any browser we tried. They did not have the issue when Vue+Developer Tools was open - making it harder for me to debug it.
Instead of the goIRList code, these users got a page with just the error message
Cannot GET /menu.csp
That was especially perplexing, because menu.csp is code from a completely different system, though one also associated with the same computer. It is never referenced in the vue-js application.
Eventually I realized that what was happening was a submit, even though the button was not in any form on the page [I had thought that a button is only a submit type by default, if it is inside a form]. As soon as I added a type, <button type="button"...>, the issue went away completely.
Could someone explain why this was happening? And why did it work for some users? Thanks!
Update: and now the problem is back, same conditions: for them and not for me. Nothing changed. I also added .prevent to the button's onclick:
<button type="button" #click.prevent="goIRList" id="irlistBtn">IR List
and no help. So maybe that wasn't the issue. Anyhow, now I'm asking for a fix as well as an explanation. Thanks!

Answer 1

Add a "submit" event catcher in the form, and prevent the default action.
<template>
<div id="app">
<form #submit="submit">
<input value="Tom">
<button>Submit</button>
</form>
</div>
</template>
<script>
export default {
name: "App",
methods: {
submit(e) {
e.preventDefault();
console.log("Success!");
}
}
};
</script>

Answer 2

And someone pointed out the answer to me. Ridiculous: those two buttons were hidden underneath a logo image that was higher up on the page. It was the image that contained the bogus link.
I never got the error, because I can't see so well, so I keep the sizing high, and the buttons were far away from the logo. Others had a more normal page sizing, and everything got smaller except for that image; the invisible margin of the image went over the buttons, and someone trying to click on the buttons triggered the link.
I set the image to resize with the page and all is well.