missing email with imap gmail

I recently moved over a hotmail account to a gmail account. Using Windows live mail (in VMware) I setup the hotmail account and gmail (imap) and copied all the mail over. It appears fine in the gmail web interface and desktop mail programs. On the iphone (imap) however, there is large gaps in the inbox email list. The last few days since the transfer show up, then it skips to 2005 emails. If I tell it to show more email it progressively fills in gaps. I can only assume that the iphone is retrieving mail based on some other time stamp such as when they arrived on gmail's server, although the dates in the message headers are correct. Any one else experience this or have any suggested fixes? I guess it will eventually not matter once enough new mail is received. Thanks.