DES MOINES, Iowa (AP) — Iowa elections officials don’t have a uniform or accurate way to check whether potential voters are ineligible felons and this has led to people being wrongly disenfranchised or wrongly allowed to cast ballots.

In interviews with The Associated Press, state and county officials cite a lack of funding, disparate use of technology at polling places and record-keeping errors. Major shifts in state policy have exacerbated the problem by creating confusion among offenders.

The Iowa Secretary of State has identified three voters who were improperly disqualified as felons in 2012, and is investigating whether there were more. Other felons who should’ve been ineligible were allowed to vote because their status wasn’t discovered until later. Some of them have since been charged with felony election misconduct for illegally voting.