The actress stepped out with Jonathan Davino in NYC Friday night, strolling down the street side by side after she attended an Armani Beauty event earlier that day ... giving each other knowing looks here and there, but mostly remaining stoic as paps fired away.

The photos mark the first time we've seen Sydney and Jonathan together in public for a minute -- over the past several days, we've either seen one or the other ... but not the two of them in one picture. Now, they appear to be trying to send a clear message.

Here's the thing ... while they, perhaps, think this should shut down any further rumors that there's trouble in paradise -- they didn't really do a good job at looking like a happy couple.

No PDA here from what we can see ... and, more importantly, still no engagement ring on Sydney's finger -- which is a look she's been sporting a lot lately -- aka, a bare digit. However, considering Jon's still walking her longtime pet on the regular ... it's hard to make sense of what the hell is going on. Like we told you, sources say they're still engaged.

Sydney and Jonathan being together doesn't translate for Glen's sitch ... whose girlfriend dumped him last week on the heels of a lot of flirtatious behavior between the two costars.

Not only were SS and GP looking hot and compatible on set for their "hard-R" rom-com, as Glen put it, but they sure seemed simpatico off-set as well ... whether it was him dipping Syd on the couch and catching her, or on the red carpet -- where they couldn't stop smiling.

At first, it honestly felt like nothing but conjecture from fans and media alike -- but after the Glen split ... some suggested there may, in fact, be flames under all this smoke.

If Sydney wants to extinguish all this full-stop ... she may have to pucker up and plant one on Johnny there. 'Cause a non-touchy-feely date in New York probably won't cut it.