Thanks for the responses everyone.
In most situations, maglock 'stickiness' is attributable to power. In the situation described above, the 'MOV (metal oxide varistor)' or diode is a good place to start.
First, it is important to verify whether or not the lock actually needs an external MOV/diode. Many installers simply get into the habit of including them and add them without thinking if they potentially can cause issues.
Many new types of maglocks include internal MOVs and do not need a separate unit installed. See this RCI installation clip with the emphasis underlined:
Also note the importance polarity can play in wiring maglock RTEs for best performance. In this RCI example, connecting the RTE interupt (pushbutton or PIR) on the wrong leg may cause the bond to collapse more slowly than expected.
Secondly, confirm the MOV/diode is connected properly. Catch this Securitron instruction below:
In this case, an external MOV is recommended, but installing it backwards changes the behavior of the component and can cause 'sticky' locks.
Ignoring the role of these small components is no answer either. MOVs/Diodes are commonly specified or included with electronic locks to prevent long term damage to supply sources when the lock's electromagnetic field collapses. The field collapse causes an effect similar to 'backfeeding' into the power conductors. Over many thousands of cycles, this can damage power supplies or connected controllers.
In any case, residual magnetism is related to the presence of electricity (ie: capacitance) in the lock circuit. Degaussing the armature or 'dimpling the lock' are unnecessary and likely would have unintended negative consequences!
Props to Tyler Graham, Timothy Mc Pheron, and Bryan Kirkland.
Stay tuned for the next access problem: "Why did my proximity cards stop working?"