Description:
in a column formatted as time hh:mm:ss, I cannot enter a time between 4:10: and 4:12:  (inclusive)
When entering the second semi colon, the displayed value turns to 4 in bold
Other times are OK

Steps to Reproduce:
1. open a spreadsheet
2. format a column as time hh:mm:ss
3. enter 4:11:

Actual Results:  
the displayed value after typing 4:11:35 becomes 435. 4 in a larger font and bold

The same is true when entering 4:10 or 4:12

Expected Results:
value should be displayed as 4:11:35


Reproducible: Always


User Profile Reset: Yes


OpenGL enabled: Yes

Additional Info:
Versie: 5.1.6.2 
Build ID: 1:5.1.6~rc2-0ubuntu1~xenial2
CPU Threads: 4; Versie besturingssysteem:Linux 4.4; UI Render: standaard; 
Locale: en-GB (nl_NL.UTF-8); Calc: group


User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:57.0) Gecko/20100101 Firefox/57.0