Ideal Icos HE35 Condensate Pipe flow?

Just recently I have found a small flood under my kitchen sink, and found that there is a build up of water from the pipe under the sink from the condensate pipe to flow into the drain.

There is nothing wrong with the drain, as the pipe is connected to the main sink drain and the water flows away as it should.

What could cause more water than usual to overflow from the boiler condensate pipe? There has not been a problem with the boiler in the last 8 years, so is there something within the boiler which is causing it now?

Probably trap blocked at the bottom of the pipe

When was the boiler serviced ?

The boiler was last serviced in July 2018