Don't doubt this is true, but if you're solely going based on which Phantoms players have been "called up" to the taxi squad recently (therefore ineligible to play in Lehigh Valley), then PHI is over the max taxi player limit. There's very clearly more maneuvering going on. https://twitter.com/TonyAndrock/status/1361381150556450818
The Flyers usually announce taxi squad call-ups publicly, but they haven't since this COVID situation has emerged. My suspicion is that the NHL is giving the Flyers a little flexibility here given the constantly-shifting nature of this situation.
To be clear, I imagine they'll ultimately stay technically compliant with roster/cap rules. But the exact way they do it each day is likely pretty complex.