Stale price and EMH

Hi all,

Trying to understand stale pricing - is it simply caused by using non-up-to-date data (e.g. real estate prices normally lags behind market conditions). Therefore, we can say real estate suffer from stale pricing ?

In the case of EMH (all 3 forms) - can we then conclude if stale pricing exist, then one can earn arbitrage through outdated info ? In this case, all three forms will be violated since we can already gain by looking at past real estate prices if they always suffer from stale pricing?

Thanks,