Tesla (TSLA) plans to temporarily suspend some of its production lines for its Model Y electric vehicle in China for three weeks, as reported by Bloomberg. The stoppage will allow for upgrades to be made to the Giga Shanghai facility.

Tesla stock was up in early trading Tuesday, following a strong Monday finish, but gains faded late in the day. It isn’t clear what drove the stock higher late Monday—or why the reverse happened on Tuesday.

Tesla (NASDAQ:TSLA) shares have been on a rollercoaster ride since their December high, but last week gave investors something to cheer about.