I've built a flyback transformer by hand for a circuit I am making and after shorting the secondary I have found my leakage inductance is very high. The primary inductance is around 2 mH, while the leakage inductance is at 1.3 mH and it is supposed to be at max only 60 uH. I have made the transformer twice now with the same result and I can't figure out what is going on.

Primary turns: 143 

Secondary turns: 6 trifilar

As requested I am providing more detail. My primary inductance is calculated by:

$$ Lp = Vin^20.5*Duty*eff/(Po*fs)  $$

Vin = 135V, Duty=0.636, eff=0.72, Po = 10W, fs =137kHz

I need to have a target primary inductanced around 1900-2000 uH, and so I need to used a gapped core. The transformer construction given by PI designer is. Note there are 3 layers of tape between primary and secondary. 

[![enter image description here][1]][1]. 

My Primary winding looks like this:
[![enter image description here][2]][2]

Shorted secondary to measure leakage:
[![enter image description here][3]][3]

Picture of core inside bobbin, there is a slight gap at the top which could potentially contribute:
[![enter image description here][4]][4]

The core material I am using is N27, core is gapped 0.17MM (recommended core gap from PI is 1.2 mm. [Here is the data sheet][5] The measurement was made on Proster 3M4070 LCR meter, accuracy should be off by roughly +/- 5 uH. The wires used for the core were not triple insulated, they are some wires I got off Amazon from [BNTechGO][6]  


  [1]: https://i.sstatic.net/r0K4w.png
  [2]: https://i.sstatic.net/P0oDQ.jpg
  [3]: https://i.sstatic.net/YycOW.jpg
  [4]: https://i.sstatic.net/yVRDc.png
  [5]: https://www.tdk-electronics.tdk.com/inf/80/db/fer/e_20_10_6.pdf
  [6]: https://www.amazon.com/BNTECHGO-AWG-Magnet-Wire-Transformers/dp/B07HRKT1WQ/ref=sr_1_1?crid=2FBEC0UE1WAS4&dchild=1&keywords=bntechgo%2028%20awg%20magnet%20wire%20-%20enameled%20copper%20wire&qid=1613326853&sprefix=BNtechgo%20en%2Caps%2C157&sr=8-1