Tasmota: Lag on Sonoff Tasmota Basic Switch

I've flashed my Sonoff Basic switch with the Atom PlatinumIO application, very easy process thank goodness. I've connected a light rocker switch to my Sonoff Tasmota and find that now and then (quite often) there is a lag when I activate it from my light switch, the button on the Sonoff or from the webpage. Silly question but, is that the current normal behaviour of the Sonoff with Tasmota firmware? If it isn't, how do I fix this? It's really annoying.

Please help.

EDIT: I should add, the lag is sometimes up to 5 seconds.
https://photos.app.goo.gl/e6KtWY1Pv2ldAYso1