Zygopetalum leafs turning brown

[euplusia]

I have Bärbel Höhn as well. When the new groth starts, water very restricted. Plants are easily overwatered in this stage and then start rotting. Also when the bulb is nearly finished, do not overwater. Last year when I went to vacation for two weeks, my neighbours killed a huge Zygo completely by overwatering and there was nothing I could do when I came back.