If you're annoyed about the incorrect arrow presentation on popovers (https://twitter.com/steipete/status/624521051855319040) use this category. Oh, and file a radar! I did.

UIPopoverPresentationController+PSPDFAdditions.m

@implementation UIPopoverPresentationController (PSPDFAdditions)

+ (void)load {
    PSPDFSwizzleMethodImplementation(self, @selector(containerViewWillLayoutSubviews), ^(UIPopoverPresentationController *_self) {
        // Refresh bar button view internals
        [_self pspdf_updateBarButtonView];
        ((void( *)(id, SEL))objc_msgSend)(_self, PSPDFPrefixedSelector(containerViewWillLayoutSubviews));
    });
}

// UIPopover positioning from barButtonItems is broken, fix it.
- (void)setPspdf_barButtonItem:(UIBarButtonItem *)barButtonItem {
    objc_setAssociatedObject(self, @selector(pspdf_barButtonItem), barButtonItem, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    [self pspdf_updateBarButtonView];
}

- (void)pspdf_updateBarButtonView {
    UIBarButtonItem *barButtomItem = self.pspdf_barButtonItem;
    if (!barButtomItem) return;

    UIView *itemView = barButtomItem.pspdf_view;
    if ([itemView isKindOfClass:UIView.class]) {
        CGRect itemRect = itemView.frame;
        CGRect navBarRect = itemView.superview.frame;
        if (navBarRect.origin.y < 100.f) {
            itemRect.origin.y -= 5.f;
        }
        itemRect.origin.x -= 1.f;

        self.sourceView = itemView.superview;
        self.sourceRect = itemRect;
    } else {
        self.barButtonItem = barButtomItem;
    }
}

@end

Oh, you'll need to replace the swizzling above with whatever helper you have - there are many ways to fix. If you don't update the toolbar on rotation, you can skip the swizzling completely. Ah, and use your own prefix, or you'll clash with PSPDFKit (if you ever need to display/edit PDFs on iOS or Android...) :)