Hi Jason,
The Open Sales Email activity is only logged if the end recipient's email client downloads all images embedded within the email. This may be the reason for not seeing the Open activity. In terms of the email link click not recorded we would want to check the URL for the link. The URL could be set in a way that Marketo does not recognize it as a link therefore not tracking it.
We definitely can get to the root of this issue by reviewing the specific examples. Please have one of your 4 authorized support contacts submit a support case with the details.