Hi Ctaylor,
Generally, this is observed behaviour if a lot of actions are performed on the records while it is still loading.
Could you please try the below steps and see if t helps:
1)Open the new lead creating page.
2)Fill in the necessary fields.
3)When using the look up to reference other records, please wait once the lookup item was selected until the loading symbol next to the lookup field is not shown any more before you continue with the next action.
4)Save the record.
Please let me know the result.
Regards,
Vivek