If you're checking for valid dates of the plate by looking at the side of the plate, you're being misled. The FAA prints two dates on the side of each plate. Although they look like expiration dates, they are not. They simply represent the print cycle of when that plate was last printed by the FAA. That is, even if a plate doesn't change for two years, every 28 days, it will have a new set of dates on the side. FlyQ ignores these dates and uses a database that the FAA publishes to download only the plates that really have changed or been added. Thus, even when all your plates are current, you may see 'old' dates on the side. You have to keep in mind that, unlike IFR enroute charts or Sectionals, there is no planned expiration date for a plate -- they just update it when necessary. Thus, it's not possible for them to print an expire date on the plate since they have no idea when it might expire.
Plates do have revision info on them in the lower left corner, however. This revision info remains constant even when the date on the side changes (unless the plate really was changed, of course) but it's hard to decode as it sometimes involves what's called a Julian date. Moreover, unless you know for sure what the "current" revision info is, it doesn't help you much as there is nothing to compare it to. We all just have to rely on the FAA accurately marking plates when changed. The good news is that we've been doing this for 10 years and we've NEVER seen them make a mistake about this.
Finally, in Tools/Options/Procedures, you can tell Voyager to download all plates, even the ones that have not changed. We do not recommend this, however, as it dramatically increases the download time.