some author slugs are uppercase?

Hi,

We’re wondering why some of our authors/stockists are being given an uppercase slug. example here: https://www.anniesloan.com/stockists/TRADER-TROVE/

When pulling through the slug using get_permalink() however it takes you to https://www.anniesloan.com/stockists/trader-trove/ as you can see in this search case: https://www.anniesloan.com/?s=trader

Was wondering if this issue is possibly caused by this plugin and if anyone has had this before?

Thanks.

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