This is not common knowledge but I found out the hard way that the Google Calendar Android app DOES NOT DISPLAY EVENTS more than about ONE YEAR away from the current date. It's a fact - which should be widely advertised. Repeated events will show but singles do not.
I Googled hard, looking for a fix. I cleared the app cache and then memory, finally re-installing the app but eventually found basically a confirmation of my discovery, inviting people to post a complaint. I CERTAINLY DID.
What a useless state of affairs for a calendar app!! I'm so annoyed and disgusted - how dare they?? I'm also double-booked as a direct result. Grrr!
It may be that you can live with it (but only knowing that fact - not as an unpublished secret) and always check on a PC or another band member's iPhone for distant (in time) bookings.
Alternatively, it's fuel for using BandHelper's Schedule system.