Hello,
after we have updated our MS Dynamics CRM instance to 2016 SP1 we got trouble with all lookup fields:
When user clicks on any lookup field, happens auto expand of Search on the field and user can't typing on the field before he makes a click again.
IMPORTANT: Use legacy form rendering setted up to "YES", we have no trouble if we set it to "No", but we have a lot of js customisations which isn't supported by new rendering.