Thanks for contacting WPML forums support. I'll be glad to help you today.
1) I can see in your screenshot the default language <wbr> doesn't have the closing site, while the translated string has it <wbr/>.
Please remove it and check if the string will be saved correctly.
2) It's unrelated to the issue, but according to your Debug.info, the WP memory limit needs to be increased. PHP memory is fine, but WordPress uses 40Mb as default. The minimum requirements for WPML are 128 MB. (Kindly check this page https://wpml.org/home/minimum-requirements/)
You can increase it by adding the following code in your wp-config.php file right before the /* That's all, stop editing! Happy publishing. */ line: