What just happened? If you've purchased Corsair's recent H100i RGB Platinum SE cooler, you'll need to reference the packaging or the cooler's radiator and see if it belongs to lot "1852," as these units appear to have a faulty seal allowing coolant to leak into the tube sleeving. If so, you'll need to contact Corsair customer support to arrange a replacement.
Corsair has issued a recall for a small number of its H100i RGB Platinum SE closed loop coolers. The affected coolers is estimated to be less than 1 percent of sold units, but Corsair insists that the recall is a precautionary measure. The leak is due to a faulty seal, where coolant leaks into the tube sleeving. Corsair notes that the leak should be immediately noticeable upon opening the box, but that it could also manifest over time.
According to Corsair, the leak should be easy to spot, as the tube sleeving is white and the coolant is bright green. The faulty coolers are limited to the lot code "1852" which can be read from the packaging or on the radiator of the cooler. All other lot codes for the H100i RGB PLATINUM SE remain unaffected. Below is a picture for reference.
Corsair encourages customers to contact them for a return and replacement, free of charge, of course. Replacements will be available beginning April 2, 2019.