Trying to run electrs in liquidregtest causes a panic

[yancyribbens]

2019-10-14T16:46:56.579+00:00 - ERROR - server failed: Error: failed to parse header 000000a044b280dac88b332f148377e133dddbde23dde180fdd9084c0c053d8f5297cb3eac20a615d9b0d4df3e3ac2cb7018a07bd314d6bb715a57adead7c03e208b36587ea6a45d01000000012200204ae81572f06e1b88fd5ced7a1a000945432e83e1551e6f721ee9c00b8cc332604b00000000010151
electrs      | Caused by: parse failed: data not consumed entirely when explicitly deserializing                                                                       
electrs      |
electrs      | electrs exited with code 1

to reproduce:

1. docker-compose up --build with the following .env

RELEASE=elements-0.18.1.1
CHAIN=liquidregtest
DAEMON_RPC=7040

2. connect to the container
   docker exec -it elements /bin/bash

3. generate some blocks with a new address
   ecli generatetoaddress 1 $(ecli getnewaddress)

[yancyribbens]

I also checked that this fails using: ecli generate 1 using deprecatedrpc=generate