Professional diver Stefan Hogerborn, part of the Ocean X team which is exploring the anomaly, said their cameras and satellite phone refuse to work when directly above the object, but they continue to work once sailed away.
"Anything electric out there -- and the satellite phone as well -- stopped working when we were above the object. And then we got away about 200 meters and it turned on again, and when we got back over the object it didn't work," the Daily Mail quoted him as telling Sweden's NTD TV.
Diver Peter Lindberg said: "We have experienced things that I really couldn't imagine and I have been the team's biggest skeptic regarding these different kind of theories.
"I was kind of prepared just to find a stone or cliff or outcrop or pile of mud but it was nothing like that, so for me it has been a missing experience I must say."
The unidentified object was first found in May last year. Sonar picture of the object resembled the famed Star Wars ship the Millennium Falcon, generating worldwide speculation.
During this visit, the team noted a 985-foot flattened out "runway" leading up to the object, implying it skidded along the path before stopping but no true answers are clear.
The mysterious object, which is raised some 10-13ft above the seabed and about 60 meters in diameter, is surrounded by a strange rock formation that expedition team can not explain.
They also found soot-covered rocks that encircled an egg-shaped hole which went into the object at its centre, and the team has no idea what it means.
"I am one hundred percent convinced and confident that we have found something that is very, very, very unique," Dennis Asberg, one of the team members, said.
"If it's a meteorite or an asteroid, or a volcano, or a base from, say, a U-boat from the Cold War which has manufactured and placed there -- or if it is a UFO... Well honestly, it has to be something."
While the Ocean Explorer team is understandably excited about their potentially earth-shattering find, others are slightly more sceptical and are questioning the accuracy of the sonar technology.
In the past, such technology has confused foreign objects with unusual -- but natural -- rock formations.
A further dive will take place in the coming weeks.
