I have multiple RB5009 each with 6 UI rockets attached. The last used port on several routers are randomly reporting "detected poe-out status: overload" . They have been working in the configuration for several months and suddenly getting this issue. Ports/router are nowhere near max output. Using 24v 14amp meanwells as the PSU. Router is receiving about 29v. Was running ROS 7.22.3, downgraded to 7.21.4 but issue remains.
In theory (from release log) 7.22.2 should have generically bettered PoE out, previous versions report fixes about PoE on specific models (but not the RB5009).
The last "fix" for the RB5009 should have happened on 7.19.6:
V7.19.6 [stable] is released!
So, what were you running when everything seemingly worked?
29V seems rather on the high side, have you tried lowering the voltage to a safer 26~27V?
RB5009UPr accepts 24V-57V input on power jack, so 29V should be fine.
However, do the power budget calculation. Device specs say that it has limit of "max total out" of 2.59A (globally, per port it's 900mA). Your power supply is way over dimensioned.
Which models exactly? I can find several Unifi Rocket models with different specifications. On a quick search one with 15W max power consumption and one with 24W max power consumption.
As already mentioned, 2.59A is max output total. 900mA each port.
At 24v this translates to max 21W each port. but considering the total of 2.59A, it is going to be less. Not 7x900mA, as this would mean total of 6.3A.
So, it well depends on the real power draw of these "rockets". As @mkx said, do the calculation.
Well, that is irrelevant (unless we are talking of energy saving), as a matter of fact such a beefy power supply should be better in the sense that even when there are peaks of consumption (if any), voiltage should be more stable than what a "tightly" dimensioned power supply would be able to provide.
Mikrotik thingies have often (let's call them) "unusual" behaviours with PoE, particularly when it comes to their "low" and "high" voltage.
In theory (per PoE standard specifications) the minimum voltage for 802.3af (at PSE, the RB5009 in this case) is 44.0 V and the minimum voltage for 802.3at (still at PSE) is 50.0V, the same voltages (at the PD) are 37.0 V and 42.5 V.
If we go by them, it would NOT be possible to have 802.3at using a 48V power supply (which is instead one of the most common voltage used for power supplies).
In practice, with 48V you can in most cases still have more than 42.5V at PD and the powered device is happy nonetheless.
There is seemingly not a clear separation line between "low" and "high" voltage, looking at other devices the "low" voltage (the one that allows 900mA max output on a RB5009 port) seems to "top" at 28-30V, maybe your 29V are just around this invisible border and in some cases it is sensed as "not low" and the available power is downgraded from 900 mA to 440mA (which is the amperage for 802.3at or however at "high" voltage).
The max voltage for PoE (again according to specifications) is 57V which, multiplied for the 440mA the RB5009 can output makes 57x0.44=25.08W which - surprise - is NOT compliant with the standard that says that you should have 30W available at PSE for 802.3at.
At 29V, with 900 mA, you would have a little more, 29 x 0.9=26.10W
BUT if - for whatever reasons - the RB5009 "believes" (always or only from time to time) to be powered with "high" voltage, it may limit the output current from 900 mA to 440mA, thus max power out on a port becomes 29x0.44=12,76W, which might cause the overload message.
The total 2.59A (or maybe the 2.28? or the 130W ?):
- Max total out (A) 2.59 A
- Total output current 2.28
- Total output power 130
are more likely to be the cause of the issues, 2.59/6=0.432A, which at 29V mean 12.51 W for each of the six used port seem below what one would normally expect.
The 130W are probably a red herring, it looks like having been calculated at 50V (50 x 2.59=129.5), at 29V 130W mean 130/29=4,49A which is 4.49/2.59=170% 
, so the max is really the "Max total out" of 2.59A or possibly the (unexplained) lower "total output current".
That's very interesting indeed! Thanks for the pointer!
I mentioned just to tell @nbhelms that power adapter rating is not the only thing limiting POE out on his RB5009.
It's not the RB5009 I'm worried about, it's the rockets. In my experience they don't like 29V.
I checked my records and I was running Ros 7.21.3 before the issue started. I have downgraded to that and lowered the input voltage to 25v however the issue persists. I seem to be able to trick it by enabling POE on an unused port and setting it to a lower priority (this atleast keeps my AP's on). My max power consumption is 72W (5009 + 6 rkts). The poe-out-consumption on the 5009 averages about 50W. Meanwell power supply is rated for 350W. I have 16 5009's in use all with similar setups but only about half are having issues.
Just read this helpful comment: RB5009UPr+S+OUT poe issues - #7 by liviu2004