Nest Shariah pension

Assalamulaikum

In my previous job I was enrolled onto the Nest Pension Scheme, I have opted into the Shariah fund which they offer. My question is that they invest in Apple, and as per IFG’s article that Apple stock may be deemed impermissible, how does one go about purifying this?
Also does the purification need to be done now or when the pension money is received after the age of 55? The % invested in Apple may change over time, how does one take this into account when trying to purify the gains?

And does the impermissible stock impact zakat calculation in any way?

My current job’s pension is with the Scottish Widows Shariah fund, again does the 5% purification need to be done on an ongoing basis or when the money is received?

Jazakallah for your assistance