Problem with Mackie Control Surface and Track Automation

Just wondering if anyone has had any problems with track automation recorded using the Mackie Control Surface.  I commonly have to mix multitrack band gigs recorded over 45 minute sets. I'll use the Mackie to ride the faders during the playback and record the mixing using the track automation.  I constantly save my work every few minutes but every once in a while I'll find that as I get deeper into the set the earlier automation I recorded is gone. I wonder if it's a memory thing as I can only imagine recording all the fader movements across at least 10 tracks probably taxes the memory or something similar.  Any thoughts?