Tight encoding uses zlib stream and VNC server can tell the client to reset the
stream before decompressing more data. Tigervnc's vncviewer doesn't implement
it correctly and interprets the data of new stream as continuation of the old
one, which leads to decompression errors.

Tigervnc's server never resets the stream, so it's not a problem with our
default VNC server, but it can be problem with other servers. Resetting the
stream is useful when a client is forwarded from one server to another.

It was fixed upstream in commit 6f318e4451fcb45054408eaf568ca1c30c2d1ab6.