ios - Long delay when pushing a UIViewController -

i have run strange issue pushing custom uiviewcontroller resulting in long delay before controller appears. if change code present controller instead of pushing there no delay.

i not doing fancy when create , push vc:

mycustomviewcontroller *myview = [[mycustomviewcontroller alloc] init]; nslog(@"myview init done"); [[self navigationcontroller] pushviewcontroller:tagsview animated:yes]; nslog(@"myview pushed"); // switching [self presentviewcontroller:myview animated:yes completion:nil] gets rid of delay 

i have added number of logs try identify when delay taking place. nslogs above print expected:

myview init done myview pushed 

then there long delay, 20-30 seconds, before of these lines print:

viewcontroller loadview begins viewcontroller loadview ends viewcontroller viewdidload begins viewcontroller viewdidload ends viewcontroller viewwillappear begins viewcontroller viewwillappear ends willshowviewcontroller viewcontroller viewdidappear here didshowviewcontroller 

all of viewcontroller logs uiviewcontroller , *showviewcontroller ones uinavigationcontroller delegate. of methods of viewcontroller seem running quickly. mentioned, if instead present same controller @ point in code there no delay. there state uinavigationcontroller can in cause this? suggestions appreciated.