I've done some Googling on this, and haven't seen anyone post about a particular and annoying problem I'm having:

On my wifi network at home, I have several possible network speakers to use for Spotify playback:

- Sony SRS x77, Sony SRSZR5 (both Spotify Connect and Google Cast)

- Yamaha RX-V575 reciver (Spotify Connect only)

- Chomecast plugged into Yamaha receiver (Google Cast only)

I've got Google Cast groups set up for various playback configurations.  Also, I have problems with the Sony speakers skipping the first few seconds of songs when using Spotify connect, so I prefer to use Google Cast for playback.

Here's the problem:

From Spotify IOS app, click 'Devices' list to send playback to a network speaker. Sometimes, I'll see only Spotify connect destinations. For speakers that support both, the little ellipsis ('...') next to the device that allows me to select the protocol I want for that speaker is missing.  The Google Cast-only device (Chromecast) don't appear in the Devices list at all, nor to Google Cast speaker groups.  This problem happened before I created speaker groups, so that's not the problem.

Generally, when this happens, I'll do some combination of: restart Spotify app, restart iPhone, and wait a while, and the Google Cast speakers and speaker groups eventually appear and are usable.  Once those appear, they work just fine (although I sure wish the client connection negotiation was faster for both Spotify Connect and Google Cast.  The problem happens both a) when I've been on local wifi network for a short time, and b) when I've been on the same wifi network for a while. It seems to be a discovery problem in the Spotify iOS app.

Yesterday, I enabled 'Show local devices only' in Spotify devices, which I hoped might solve the probem, but did not.

I'm at a loss.  Anyone else experiencing this problem and have a workaround/fix?

thanks

sal