Which version of the application is this, and exactly which field are you referring to? 
A screenshot would be good. Would also be good to understand why the journal isn’t suitable for these types of comments.

• Please first check the form template xml if <meta-enforce-rte-limit> or <meta-enforce-plain-text-length-limit> is configured as "true". For further details, please refer to KBA 2372468 - How to Check if the Performance Form has a 4000 Character Limit.
• If so, there will be 4000 character limit on comment fields and custom textarea fields.
• Currently it is expected system behavior that when the above codes are added, texts are counted by byte. Therefore, for double-byte languages like Chinese, Japanese etc, since each character can take 2 or 3 bytes, the limit is reduced to around 1300 characters. 
• Comment fields will dynamically expand as the user enters text that exceeds the standard height of a comment field. 
• Form Comment Fields: 4000 characters is roughly equivalent to one or 2 web pages or word document pages of about 650 words including spaces. The 4000 limit is per field, and not per form, so if you have a need to allow more than 4000 characters/bytes of text, then consider adding some custom fields to capture this information. Please keep in mind, that a comment box is intended to be that, an option to capture brief comments, as opposed to larger documents, feedback, or information, so the 4000 character/byte limit is considered very generous for its designed purpose.
• Route Comment Field: When you route a form, you may have enabled the Route comment field. This comment field has an even smaller limit of 2048 characters for single-byte characters like English or about 700 for languages such as Chinese & Japanese that do not use single-byte characters.
• In addition to these natural field limits, it is also possible to configure certain goal fields with a maxlength attribute min-value and max-value, so that you can reduce how much text is entered into the field.
• You can also configure minimum and maximum value for required fields so that the system will check for how much text is in the field when moving from one step to the next and preventing the form from moving if it exceeds the desired length. But please note that <meta-enforce-rte-limit> and <meta-enforce-plain-text-length-limit> also take effect on required fields which means that for example, even if you configure maximum value 1000 for a textarea type field, you can only enter around 300+ Chinese, Japanese and other double-byte languages.

NOTE: