When Save() is called on an IAAFFile object, the
LastModified property on the Header is not updated and
is written as 0000-00-00-00-00-00 (aafTimeStamp_t).
Workarounds to make LastModified's value the current
(a) Call Save() twice in quick succession.
(b) Create some embedded EssenceData via the
Occurs in version 1.1.0 and 1.0.2 of the AAF SDK.