Try using a pistol and then using cannons skill ( with cannon as your alternate weapon) it does have a little lag lol
The lag is actually due to the server sending checks to your character to ensure that your character is holding the correct weapon stance.
Auto swap mechanics works like this.
If you are not using the correct weapon stance it will show
(your character is using the wrong weapon)
(tapping too fast)
It’s extremely visible esp with charged skill or hold on skill.
Quick cast skills will experience the most. Like snipe, and headshot.
Hold to charged full skills have minimal impact.
Same applies actually to multi shot types but when you need to release early it proc wrong weapon like quick tap.
If you question is it a ping issue. I will say it’s not i have way lower ping than you expected normally around 10-20ms total.
It’s just poorly coded weapon swap + stance check.
Also this is the main reasons why Koreans player assign weapons to hotkey. To ensure manual swapping so that it will not “roll back” to the auto swap and screw up the skills he wanted to cast.