I went to visit the park together with Ike Suriwong. Nick Upton had reported a Sakhalin Leaf Warbler singing in the park last weekend and that is something I haven't experienced.
We ended up seeing two Pale-legged/Sakhalin's Leaf Warblers. None of them were calling but one was singing, clearly revealing its identity. The two species have very different songs and can only be separated safely by song or in the hand.
There were other migrants in the area. 1 Yellow-browed Warbler, 1 Arctic Warbler, 1 male Green-backed Flycatcher seen by Ike and sadly not by me, 1 female Yellow-rumped Flycatcher and a very active flock of 40 Ashy Minivets. Also two cute Forest Wagtails on the floor added to the migratory bird list.