Smart meter users have been left a little confused after their readings changed from English to Welsh.
Bulb energy customers have been reporting the language glitch on their devices, which has been described as 'rare' by the company.
It is believed that the random switch has affected around one in 200 metres, even though some customers live more than 100 miles away from Wales.
The problems didn't stop there. When those hit with the error tried to fix the problem the language of the device's settings menu had also changed.
You can see the problem.
Users noticed the switch after the 'usage today' indicator changed to 'defnydd heddiw'.
A spokesman said: "In some rare cases, In-Home Displays switch to Welsh.
"While we think Welsh is a great language, we understand that in many cases people will want their display to be in English.
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"Luckily the solution is just a few button presses away, and language settings can be changed in less than 10 seconds."
James Tombs, who lives in West Sussex, more than 100 miles from the Welsh border, told the Money Saving Expert website: "I don't live in Wales and don't know Welsh ... I went on to the Bulb forums, found others with the same problem and followed directions to change (the) language.
"It has been fine since."
Bulb was forced to post a solution to the issue on its own website after several customers complained.
If you find yourself affected you need to follow these instructions:
"Press the 'OK' button at the bottom of the In-Home Display, and then the right arrow button until you see 'Gosodiadau Wedi anfon yr'.
"Press OK. This takes you to settings.
"Press the right button until you see 'Dewis iaith Wedi anfon yr'. (If this doesn't work, you may need to try the next option, 'Clirio Gosodidau Wedi anfon yr').
"Press OK.
"Select English on the left, by pressing the left arrow, then 'OK'."
