Attempt to rotate an image creates "img not captured"


Using the example code for the Simple watch (Batman dial) shipped with the TTGO T-watch library. I have replaced the watch face, re positioned the time display, changed the font and removed the seconds count.
I want to rotate an image of a pointer to represent seconds. I’ve created the pointer image (img2), positioned it and can rotate it with lv_image_set_angle().
The code i’m reusing creates an lv_task to update on screen elements.
Trying to change image angle within the task fails with “img2 not captured”
Trying to change the angle within the main loop between lv_task_handler calls, compiles but the screen is then blank.
I’ve also placed the image angle change into its own routine and calling it from the task and the main loop. This gives a blank screen in both cases.

What MCU/Processor/Board and compiler are you using?

Lily-Go T-Watch with Arduino 1.8.19

What LVGL version are you using?

Twatch distribution. LVGL V 7

What do you want to achieve?

A rotating second hand from an image over a watch face from an image

Code to reproduce

LV_IMG_DECLARE(raym); //watch face
LV_IMG_DECLARE(pointer);  /second hand

void setup()

    watch = TTGOClass::getWatch();

    lv_obj_t *img1 = lv_img_create(lv_scr_act(), NULL);
    lv_obj_t *img2 = lv_img_create(lv_scr_act(),NULL);
    lv_img_set_src(img1, &raym);
    lv_img_set_src(img2, &pointer);
    lv_img_set_pivot (img2, 8, 120);
    lv_obj_align(img1, NULL, LV_ALIGN_CENTER, 0, 0);
    lv_obj_align(img2, NULL, LV_ALIGN_CENTER,0,-50);
/* Block of formatting for text removed for clarity*/
    lv_img_set_angle(img2,2800); //--------------- This works OK
    lv_task_create([](lv_task_t *t) {
        RTC_Date curr_datetime = rtc->getDateTime();      
        lv_img_set_angle(img2,300);//------- This fails with "img2 is not captured" ---------------
        lv_label_set_text_fmt(g_data.minute, "%02u", curr_datetime.minute);
        lv_label_set_text_fmt(g_data.hour, "%02u:", curr_datetime.hour);
    }, 1000, LV_TASK_PRIO_MID, nullptr);

void loop()
    //lv_img_set_angle(img2, 300);  //------------ this results in blank screen -----------------