This is probably a minor bug regarding the bouncing Marketo logo which appears on the first load of the new UI. This is fine as a one-off tutorial element, but when clicking through to a lead record via an alert email (the {{SP_Send_Alert_Info}} token), this logo is constantly bouncing due to it having the "mkt-app-logo-attention" class.
If possible, this should be removed when viewing a lead record, as it's quite distracting when trying to scrutinise activity log data! 🙂