PHP error. Array to string conversion

Hi.
I’m using Query Monitor and it’s show me that

Array to string conversion

location:
wp-includes/formatting.php:703

Call stack:
wp_check_invalid_utf8()
esc_attr()
tempera_custom_styles()
tempera_styles_echo()
do_action(‘wp_head’)
wp_head()
load_template(‘…/wp-content/themes/tempera/header.php’)
locate_template()
get_header()

Component:
Core

is it normally???