Do you know the name of the cultivar that is doing this? There are repeat-blooming cultivars of Bearded Iris (Iris x germanica cvs.) so this could be an especially floriferous example of one of those. Usually though the bloom in Spring and again in Fall, not continuously.
If other plants of the same variety are not doing this, then it is especially amazing. Most likely this is a non-reproducible freak occurrence, but then again, perhaps that plant has sported (mutated) somehow.
In that situation, if there is a stable genetic basis for this, you could have a lucrative cultivar in your possession. Keep an eye on that plant next season and see if it repeats the stunt.