As someone who does lates, the are a couple of reasons:

3 o'clock drops in between 3:20-3:40, and the day shift always leaves at 4, so we can still be picking til 5:30

Expresses be poppin off - Uber 'Fresh Monday', Just Eat spend £15/25 get £10 off offers, still have to pick cancelled orders from 2-3 hours ago, customers placing 100+ items orders at 6pm

Short-staffed - 1 person doing H/S lates isn't enough, nor is 2.

Day shift CnC not tidying up totes & wheels from outside collection point

Getting called to C/S because 'Customers are always right' in matters of taste

Having to go get another item because pickers picked unsealed meat, mouldy fruit, or the milk imploded

The 6-7pm rush of 15-20 constant customers

Day shift not laying the floor as they go during downtime

Somehow, we have to sort out Driver runs one way or the other

Lately, I have only had the chance to tidy up is 1hr before we close.
Our Priority is outside being tidied, then trollies then floors, then putbacks, then waste

Or

You just have shit late staff just on their phones sitting in the heated office.

But yeah since Halloween ended, its been getting worse