Ionic icons loading issue

Hey, during the development it has been really hit and miss whether i get to see the icons.

As you can see here: https://gyazo.com/15c3ebb8f4a57102ccebdd051af9d64e

However they do sometimes render.

I was wondering if anyone can tell me whether this is a common occurring issue or whether it’s something i need to fix, and if so, how.

Thanks in advance.