Two lawsuits filed yesterday in US District Court in Boston claim Wells Fargo and Bank of America have not followed federal rules for mortgage loan modifications, leaving some homeowners stuck in foreclosure “limbo.’’ According to one of the lawsuits, Wells Fargo Bank North America did not honor agreements with Wilfredo and Odalid Bosque of Leominster and Germano DePina of Roxbury that would have made their temporary loan modifications permanent through the US Treasury’s Home Affordable Modification Program.