If you give 80,001 characters to a Text Area you get a message and the record is not saved.
a) If you set a "Maximum number of text characters in input" the maximum value you can type is 9999, strangely not 80,000.
b) If in this instance you give 80,001 characters the record is saved, the Text Area value being silently truncated to 9999 characters.
These seem a little inconsistent.
I have tried on Rollbase 5.0 and below were my observations.
80,000 as max allowed characters for text area is derived from Shared Prop Value : MaxDbLongStrLength. It's default value is 80000. If you want to save value greater than 80,000 - consider increasing limits through shared prop value.
a) This is reproducible. We have accepted this as Bug - 41527.
b) This was also reproducible. However, i would just like to point out that truncation happens at source or client-side. If any limits are specified on the field like 9999, Text Area Input box restricts user to enter at most 9999 characters. You may not have noticed this as we could be testing with garbage data just to check length limits. So, while you may have pasted 80,001 characters in input box - the text area would have retained at most 9999 characters. Upon form submit, server side would have received just 9999 charcaters instead of receiving 80,001 and silently truncating to 9999.