Elite: Dangerous recently revamped with the release of a big new expansion. But one of the unintended consequences was it made AI spaceships incredibly powerful - so powerful, in fact, that developer Frontier was forced to strip them of their upgraded weapons.

The Engineers are hidden on planet surfaces across the populated galaxy. Each has a unique personality and history.

The Engineers (2.1) expansion made key changes to the space game's AI and NPCs. The intention was that higher ranked NPCs would be harder to beat than ever before, providing players with a tougher challenge.

Players quickly discovered that this challenge was too tough - and took to Elite: Dangerous' forum and sub-Reddit to complain.

Frontier responded by removing almost all Engineers upgrades from the NPCs in the game, a move designed to help players deal with NPC threats and last longer in a combat situation.

Players also complained that the Engineers update had made NPC behaviour overly aggressive, and that they were now being attacked without being "wanted" or carrying any cargo of note.

In Elite: Dangerous, players can be "interdicted" - that is, they can be pulled into combat situations by other spaceships. Players have found post-The Engineers, NPC spaceships try to do this to human controlled players much more often. And this, coupled with the powerful new upgraded weapons, meant the AI was devastatingly dangerous.

The situation got to the point where a lot of players - even those experienced with the game's combat mechanics - dared not venture out in anything other than a combat ship or an extremely fast ship. The video, below, shows just how quickly AI spaceships can now kill players.

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By stripping the NPCs of their upgrades, Frontier hoped to be able to review the effectiveness of the AI on its own to see if it needed to make balance changes.

That was at the end of May. Now, at the start of June, Frontier has discussed its ongoing investigation into Elite: Dangerous' super aggressive, super powerful AI, and reckons it's worked out what went wrong.

According to a post on the Frontier forum, the developer believes The Engineers shipped with a networking issue that let the NPC AI merge weapon stats and abilities, thus causing unusual weapon attacks.

By smuggling materials to the outposts of the Engineers, players can earn their respect to unlock powerful module upgrades.

This meant "all new and never before seen (sometimes devastating) weapons were created, such as a rail gun with the fire rate of a pulse laser".

The issue was compounded, Frontier said, by the additional stats and abilities of the engineers weaponry.

"We don't think the AI became sentient in a Skynet-style uprising!" Zac Antonaci, Frontier's head of community management, said.

"I would just like to take this opportunity to clarify a few misconceptions," Antonaci continued, addressing concern around the spaceship AI.

"The AI has in no way been reduced, it remains the glorious, improved version from the update. The only action that we've taken so far has been to remove the engineer weapons to allow us to investigate the issue and address a key bug."

Today, a bug fix was issued to the PC version (the Xbox One update will follow). This stops NPCs ending up with overpowered hybrid weapons, and rebalances the ambient AI rank chances.

Here's the relevant part of the patch notes:

NPCs:

Fix NPCs ending up with overpowered hybrid weapons.

Stop NPCs deciding to attack if they only attack opposing powers and the player and AI powers are aligned to the same superpower.

Slight rebalance of the ambient AI rank chances, should see slightly less of the top end and more of the low/mid range.

Smooth out the mission-spawned USS AI levels so that high ranks are rarer and only elite missions hit the top end AI (though deadly can get close).

Antonaci said Frontier will cast a fresh pair of eyes over the AI now the bug fix has gone live and, if it feels the balance is where it should be, introduce a very select few high-end engineers weapons to the highest ranked NPCs.

"However, that won't be immediately as we want to ensure that the balance is just right," he said.

UPDATE 3rd June 2016: Frontier has said it'll automatically refund all insurance costs to players who lost a ship between the launch of The Engineers (2.1) update and this morning's update.

"Due to the recent surge of unsanctioned and illegally modified weapons from the NPC AI over the recent days," a post on the Frontier forum reads, "The Pilots Federation have agreed to reimburse all insurance payouts made over that period (Between The Engineers (2.1) update and this mornings update)."