Sorry for cluttering the Electrum forum with an Electron Cash question, but I was hoping someone who had used it could chime in. Is there an official forum somewhere?

I wanted to split a little bit of BTC into BCH. The first attempt using Electron Cash was successful. The second was not, and resulted in a transaction the server did not accept ("non-canonical DER signature").

Has anyone encountered this problem and knows what the cause might be?

One difference is that the first transaction spent a p2pkh uxto and the second one spent a p2pk. Has anyone spent a pay-to-public-key uxto with Electron Cash and did it work?