Game instance crash and lag spike when entering new area

Im playing on SEA server (singapore) with 30-40 ping average, everytime i change area like entering new map, transition area in lab or entering vaal place,i get lag spike or disconnect due to latancy increased but my internet is stable. The lag spike i can kinda fix by re-entering the zone by portal till it gone, but it get tiring when you doing lab and disconnect thus losing all progress. Help please, only happen in Experdition league, before its fine.