Based on my investigations... the "Save" option on the "Send" tab in Android Electrum (the little diskette icon), simply saves the "invoice" into your wallet file... It is not used like the "save" option in the desktop client for being able to export transactions for signing offline.
...
"invoices": {
"1dummyBitcoinAddress": {
"hex": "22291xxxxxxxxxxxxx[redacted]xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx6f6f2a00",
"requestor": null,
"txid": null
}
},
...
Of course it is. Unlike the great Desktop version the very restricted Android Electrum wallet application does NOT have an Export button !
(Which personally I do use always for exporting unsigned transaction for signing offline