No time displayed by few 1 Action visits

[melbao]

Hello,
i have observed a phenomenon. By few 1 Action visits, there is no time on page displayed in (same visit)

– Visitors → Visits Log - cards
– Visitors → Real-time - rows

but “0 seconds” are displayed in (same visit):

– Visitor profile - Summary
– Real-time - cards - black popup

A phenomenon becaus my JavaScript tracking code:

setInterval(function() {
  if (document.readyState === "complete") {
    setTimeout(function() {
      // load matomo.js
    }, 1100);
  }
}, 100);

A tracked visit is also min 1 second on the page. Hint: matomo begins the time on page from the loading of the page.

My question is: Is this a bug or has it an another reason?